KR20210134135A - Method of securing text and device implementing thereof - Google Patents

Abstract

The present invention relates to a method for securing text and an apparatus for implementing the same. An encryption device according to an embodiment of the present invention generates an encryption font and encrypted text instructing to reproduce original text or character string as a different character or character string according to an encryption method.

Description

METHOD OF SECURING TEXT AND DEVICE IMPLEMENTING THEREOF

The present invention relates to a method for securing text and an apparatus for implementing the same, and more particularly, to a method for securing text based on a multi-substituted security font and an apparatus for implementing the same.

Due to the rapid development of current computing systems and network systems, variously written text documents are easily exposed to undesired people in storage places or during transmission. In order to solve this problem, various security technologies have been developed. However, these document security methods are biased toward security by user authentication, etc., and remain defenseless when user information is exposed.

In addition, there has been a problem in that the 1:1 substitution of characters in the text can be easily inferred depending on the number of appearances of the characters. Therefore, it is necessary to develop a technology to secure the text in a new way.

The present invention intends to implement a method and apparatus for increasing the security of a document by encrypting the original text, but restoring it by applying an encrypted font.

An object of the present invention is to implement a method and apparatus for increasing the encryption level by applying various encryption methods to a single document and reducing computing power in restoring it.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned here will be clearly understood by those skilled in the art from the following description.

The encryption device according to an embodiment of the present invention receives a font, an original text, and identification information indicating an encryption method for encrypting the text, and replaces one or more characters of the original text according to the encryption method indicated by the identification information. and a conversion code generator for generating a conversion code corresponding to a character code or a string code to be converted.

An encryption apparatus according to an embodiment of the present invention includes a substitution rule generator for generating a substitution information set including a substitution rule corresponding to a conversion code.

An encryption apparatus according to an embodiment of the present invention includes a text converter for generating encrypted text by converting one or more character codes of the original text according to a substitution rule.

An encryption device according to an embodiment of the present invention converts and encrypts the character code character-pattern mapping information (cmap) and transformation and ligature information (GSUB) or design information (glyf) of the font in response to the replacement information set Includes a font generator.

In the method for encrypting text according to an embodiment of the present invention, a conversion code generator of an encryption device receives a font, an original text, and identification information indicating an encryption method for encrypting the text, and then converts one or more characters of the original text to the and generating a conversion code corresponding to a character code or a character string code to be substituted according to an encryption method indicated by the identification information.

A method of encrypting text according to an embodiment of the present invention includes generating, by a substitution rule generator of an encryption device, a substitution information set including a substitution rule corresponding to the conversion code.

A method of encrypting text according to an embodiment of the present invention includes generating, by a text converter of an encryption device, one or more character codes of the original text according to the substitution rule to generate encrypted text.

In the method of encrypting text according to an embodiment of the present invention, the encryption font generator of the encryption device corresponds to the replacement information set, and the character code character-design mapping information (cmap) of the font and transformation and ligature information (GSUB) or Converting and encrypting the design information (glyf).

An encryption device according to an embodiment of the present invention converts one or more character codes of the original text using a controller that receives fonts and original text, a conversion code required to encrypt the text, and a replacement information set stored in a replacement rule storage A text converter that generates an encrypted text by doing so, and a character code character-pattern mapping information (cmap) of the font corresponding to the replacement information set, and a transformation and ligature information (GSUB) or design information (glyf) converted and encrypted. Contains an encrypted font store where fonts are stored.

The method for restoring encrypted text according to an embodiment of the present invention includes the steps of: obtaining, by a restoration apparatus, encrypted text and an encrypted font corresponding to the encrypted text; and applying the encrypted font to the encrypted text so that the encrypted font is applied. and displaying a text including a second character displayed differently from the first character of the previously encrypted text.

When an embodiment of the present invention is applied, it is possible to generate text with an increased encryption level by diversifying rules for exchanging or replacing character codes.

When an embodiment of the present invention is applied, multiple substitution between characters, character-string, character-string-to-character, and string-to-string encryption are enabled.

When the embodiment of the present invention is applied, the encrypted text can be protected while the original text is reproduced by applying the encryption font to the encrypted text without a separate decryption process.

The effects provided by the present invention are not limited to the above-mentioned effects, and other effects not mentioned herein will be clearly understood by those skilled in the art from the following description.

1 shows a process of encrypting and restoring text according to an embodiment of the present invention.
2 shows a 1:N multiple mapping process, which is an embodiment of multiple substitution for text security according to an embodiment of the present invention.
3 shows a detailed mechanism of a method of substituting a character in FIG. 2 according to an embodiment of the present invention.
4 shows a process of sequentially performing 1:1 substitution and multiple substitution between characters according to an embodiment of the present invention.
5 shows a process of converting one character into a character string including a plurality of characters according to an embodiment of the present invention.
6 shows a process of converting one character string into one character according to an embodiment of the present invention.
7 shows a process of converting one character string to another character string according to an embodiment of the present invention.
8 shows an information set required to perform substitution in an encryption method according to an embodiment of the present invention.
9 shows the configuration of an encryption device according to an embodiment of the present invention.
10 shows an encryption process of a secure font according to an embodiment of the present invention.
11 to 14 show examples of encryption and restoration according to various encryption methods of the present invention.
15 shows a process of reconstructing and displaying the encrypted text according to an embodiment of the present invention.
16 shows a process of restoring a ciphertext according to an embodiment of the present invention.
17 shows a process of recovering a ciphertext according to another embodiment of the present invention.
18 shows the configuration of an encryption system according to an embodiment of the present invention.
19 and 20 show the configuration of an encryption system according to another embodiment of the present invention.

Advantages and features of the invention presented in this specification, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed herein, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and are common in the art to which the present invention pertains. It is provided to fully inform those with knowledge of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are given to the same or similar elements throughout the specification. Further, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It will be understood that each component may be “interposed” or “connected”, “coupled” or “connected” through another component.

1 is a diagram showing a process of encrypting and restoring text according to an embodiment of the present invention. Devices that encrypt or restore text include a variety of devices, such as computers, laptops, smartphones, and tablets.

The encryption device 110 may generate a result of encrypting the text (S1) and upload it to the server 300 or the like (S2). And when the restoration device 120 requests the encrypted text uploaded to the server, the encrypted text is downloaded to the restoration device 120 (S3). In this process, the restoration device 120 may download information necessary to restore the text, for example, a font.

Alternatively, the encryption device 110 may directly transmit the encrypted result by performing multiple substitution of text to the recovery device 120 (S4). This includes an embodiment in which the restoration device 120 and the encryption device 110 can communicate on a 1:1 basis.

The restoration apparatus 120 performs restoration by applying a font to the encrypted text (S5). As a result, the restoration apparatus 120 may display readable text.

Multiple substitution methods for text security include 1:N multiple mapping, character:string multiple mapping, string:character multiple mapping, and the like.

The 1:N multiple mapping means that there are N (N > 1) arrival characters encoding a specific character included in the text, for example, the starting character "A", which is the character before being encrypted.

Accordingly, the arrival character that encodes the starting character of “A” may be multi-mapped to “right”, “do”, “H”, or the same “A”. Thus, "A" in the text may be multiple substituted with "right", "degree", "H" or "A" when multiple substitutions are made.

Accordingly, the text character "AAA" may be substituted with "helpH" or "likelihood" or "AdoH" or the like.

The character:string multiple mapping is a method of mapping one starting character to an arrival character string. For example, the encryption device 110 may replace one starting character “A” with an arrival character string “FDSADS043219231jfdakjdsf”. That is, an arrival string composed of two or more characters is generated corresponding to one starting character.

String:multicharacter mapping is a mapping of a starting string consisting of multiple characters to a single destination character. For example, the encryption device 110 maps the starting string of "Nice to meet you" to the arriving character of "K".

2 shows a 1:N multiple mapping process, which is an embodiment of multiple substitution for text security according to an embodiment of the present invention.

The 1:N multiple mapping is an embodiment in which two or more characters are mapped to one character and encrypted. A mapping rule as indicated by 11 of FIG. 2 shows a substitution rule in which one character is mapped to a plurality of characters.

11 , the encryption device 110 may encrypt the letter “e” as “many” or “t” depending on the situation by applying a mapping rule or a substitution rule. Depending on the situation, it means that the encryption device 110 may select randomly or according to the number of appearances or the number of appearances of an encrypted character in a sentence previously.

In addition, the encryption device 110 may multiplex "e" to be expressed as "e" without additional conversion.

The other encryption device 110 may also encrypt "o" as either "wet" or "knee". Similarly, the encryption device 110 may encrypt “l” as “many” or “H”.

Also, the encryption device 110 may apply 1:N multi-mapping only to characters that appear repeatedly in a sentence to be encrypted. For example, 1:1 mapping can be performed on a character that appears once in a sentence to be encrypted, and multiple mapping can be performed only on a character that appears twice or more.

Let's look at these examples. In FIG. 2 , the encryption device 110 may maintain mapping rules for all characters. In particular, the encryption device 110 may perform 1:N mapping for repeated characters in the original text 12 .

As a result, the encryption device 110 may encrypt the original text 12 into the cipher text 13 .

In an embodiment, the encryption device 110 maps the English character "e" of the original text 12 to any one of {e, t, and da} according to the mapping rule 11, respectively.

In addition, the encryption device 110 maps the English character "o" of the original text 12 to any one of {wet, ni} according to the mapping rule 11, respectively.

In addition, the encryption device 110 maps the English character "l" of the original text 12 to any one of {da, H} according to the mapping rule 11 .

In addition, the characters not included in the mapping rule 11 are <t/n/r/u/c/S> and <t/n/r/u/c/S> according to the 1:1 mapping rule. They are encrypted so that they can be exchanged 1:1 with each other.

On the other hand, <wet/H>, which appears once in the original text 12, but appears as an encrypted character in the mapping rule 11, is mapped to <o/ l> by applying the mapping rule 11 in reverse. do.

In addition, while "knee" is 1:1 mapped to "F", it can also be mapped to "o" by applying the mapping rule 11 in reverse.

2 is a method of selectively substituting one character among a plurality of characters. 3 shows a detailed mechanism of a method of substituting a character in FIG. 2 according to an embodiment of the present invention.

The encryption device 110 may use any one or more of a True Type Font (TTF) and an Open Type Font (OTF). In FIG. 3, 21 shows a TTF font structure, and 22 shows an OTF font structure. In the 1:N mapping, 1:1 substitution between characters and multiple substitution between characters is performed as an embodiment. In more detail, 1:N mapping includes a method of changing character design information for character codes as shown in S25. In addition, 1:N mapping adds multi-modification information for character design as shown in S26.

Let's take a closer look at S25. The Unicode of the character "A" is 0x0041. And the gid (glyph id) for displaying "A" on the screen is 36. Here, when changing cmap information (ie, character code character-design mapping information) as in S25, Unicode is maintained and only its displayed gid is changed to 43. As a result, "A" is displayed as "H". That is, S25 may perform encryption by changing cmap, which is character design information for a character code (Unicode).

S26 will be examined in detail. Separately add information to the GSUB of the letter "A" (ie, transformation and ligature information). As a result, a design of "J" with a gid of 45 is added as multiple variant information for a character design. That is, S26 can perform encryption by adding multiple transformation information for a character design to the GSUB.

4 shows a process of sequentially performing 1:1 substitution and multiple substitution between characters according to an embodiment of the present invention.

As shown in FIG. 2 , a mapping may be made directly between the original text 12 and the cipher text 13 , and an intermediate cipher text 15 between the original text 12 and the cipher text 13 may be disposed. The intermediate cipher text 15 is a result of 1:1 substitution for each character of the original text 12 in the process S31. For example, "e" and "da" are mutually substituted characters (S31). As shown in S31f, the gid (glyph id) 72 of "e" is changed to 15345 to indicate "many", and the gid that displayed "many" is also changed from 15345 to 72 indicating "e". changed This means that "e" and "c" are substituted 1:1 with each other.

As a result, since 1:1 substitution is performed in the intermediate ciphertext 15, the letter "e" is displayed as "Da", and the letter "Da" is displayed as "e".

At this time, since the letter "da" is repeated three times in the intermediate ciphertext 15, it can be applied as a multiple substitution.

As a result, the letter "da" is replaced with the letter "t" or "e" again, and this process is presented in S32b/S32c/S32f. As a result, as indicated by 11, the letter "e" may be replaced with any one of dart/dot/e according to the 1:N mapping process.

2 to 4, when an encryption method by 1:N mapping that converts one character into one or more characters is applied, the characters repeatedly appearing in the text of the original text are converted to different characters. can be converted For example, if only 1:1 mapping is performed, if the word "geese" is encoded, the first letter "ki" is converted to "a", and if the second letter "ru" is converted to "3", the last letter "Gi" is converted to "a" and converted into "a3a" form. Since the letter "a" is repeated, it is easy to infer that the letter "a" has been substituted from a certain letter. On the other hand, if the third character "ki" is converted to "k" and encrypted as "a3k", it is difficult to infer that the characters "a" and "k" are actually conversions of the same character, and it is difficult to infer the security of the cipher text. can

Next, let's look at the substitution that converts a single character into a string. This is an embodiment in which one character is replaced with a character string. This is different from the substitution of Figs. 2 to 4, wherein in the 1:N substitution of Figs. 2 to 4, one letter of the original text is replaced with one letter of the cipher text, but various letters of the cipher text can be presented for one letter of the same original text. There is an embodiment.

An embodiment of replacing a character with a character string includes mapping a character string composed of two or more characters to one character and including the character string in the cipher text.

5 shows a process of converting one character into a character string including a plurality of characters according to an embodiment of the present invention. Strings are mapped as indicated by 35, 36, 37, and 38 for each of the single characters "bo", "an", "phon", and "t". Therefore, when the original text is "secure font", the cipher text is a result of summing all the strings of 35, 36, 37, and 38 into one (S39).

As an embodiment of the encryption method, a hash function value of a character code may be used as an encryption string. In this case, the original text content can be restored without a separate decryption process by composing the ciphertext only with the hash function value.

The encryption method for converting a single character into a single character string as shown in FIG. 5 can be used to make it more difficult to infer the original text by applying a character-by-character transformation. For example, if the character "han" is transformed into the string "hello" and encrypted, it is very difficult for an external user or hacking program to infer the character "han" from the string "hello". Also, the encryption device 110 may convert a hash function value "eddea29aaace3b9f6c961f82be64b57d7d0e3a7a" to which a hash function is applied to "one" character. Since this is a complex transformation, it means that it is not easy for an unauthorized user to restore it. When one character is converted into a string in this way, a very complex ciphertext can be generated. And, most importantly, it is not necessary to implement additional logic in the receiving device to decrypt this ciphertext. Since the process for reproducing the original text for the cipher text is performed inside the font, there is no need to deliver the decryption logic and conversion rule to the outside.

6 shows a process of converting one character string into one character according to an embodiment of the present invention. Contrary to FIG. 5 , the text string of the original text may be encrypted with one character. 6 shows a process in which a character string of the original text is converted into one character. It is a method in which one character code is mapped for multiple characters.

41 of FIG. 6 shows an example of converting the string "Nice to meet you. This is secure font 2!" into the letter "i". And 42 is "Hello, SecureFont 2!" It shows an example of converting the string "h" to the letter "h".

As a result, the original text "Nice to meet you. This is SecureFont 2! Hello, SecureFont 2!" is converted to the ciphertext "ih" by reflecting 41 and 42. This procedure is indicated in 43. As shown in FIG. 6 , the encryption method for converting one character string into one character can give an effect of compressing and encrypting the original text. As shown in FIG. 6 , since one character (h, i) replaces a certain sentence, an external user or a hacking program cannot restore the original text.

In particular, if a simple conversion between characters (eg, S31 of FIG. 4 ) is applied to the entire original text and then compressed into one character for important words or sentences, the main phrases can be more safely protected. In addition, since a plurality of character strings are converted into one or more characters, a ciphertext composed of only a few characters can correspond to multiple sentences.

In addition, when performing the multiple conversion as described in FIGS. 2 to 4 and compressing and converting repeated words or important words or sentences into one character, the compression effect and the encryption effect can be obtained at the same time.

7 shows a process of converting one character string to another character string according to an embodiment of the present invention. Maps a string of m characters to a string of n characters. In this case, m and n may be the same number or different numbers, and when m and n are different numbers, either m > n or m < n. This is an encryption method that replaces one sentence (string) with a sentence (string) composed of completely different characters.

45 of Fig. 7 shows an example of converting the string "Nice to meet you. This is secure font 2!" into the string "fr8759". and 46 is "Hello, SecureFont 2!" It shows an example of converting the string "84002a7" to the string "84002a7".

As a result, the original text "Nice to meet you. This is SecureFont 2! Hello, SecureFont 2!" is converted to the ciphertext "fr875984002a7" by reflecting 45 and 46. This procedure is indicated at 47.

Conversion rules of various methods can be applied to encrypt one string into another string. Various conversion rules such as conversion between words and words, conversion between words or word phrases and phrases, conversion between sentences and words, conversion between sentences and sentences may be applied.

For example, in the case of encryption using word-to-word conversion, the word "Hangeul" can be converted into an arbitrary word with different lengths of "han", and can be converted into the obfuscated word "Tgapgu" Alternatively, the hash function value "0xde510ee18f9ec63431a640b3fe6823ca9013da91" of "Hangul" can be designated as a conversion word.

Since the hash function value has a unique value for each character or string, when the original string is converted to the hash function value, an external user or hacking program cannot restore the original string from the ciphertext. Due to these characteristics of the hash function, it is widely used in password encryption. It provides a very strong encryption function because it can be specified as a converted string by utilizing the strong encryption function of the hash function.

It is also possible to convert the string "Hangeul", which is a form with a suffix and a suffix, into another string. The string "Hangul" can be converted to the string "hangul", and the obfuscated string "Stylus? Star▶?" It is also possible to convert to or convert to a hash function value.

It is also possible to convert a string to another string for an entire sentence. It is possible to convert a sentence into a single word, a word ending with a postposition, or a single sentence.

When one original document is encrypted by the string conversion method, it is possible to designate a sentence to be converted for words, phrases, and sentences in the original document. Encryption conversion for the original document can be specified so that a unique rule is applied by the conversion key value. If the conversion key value is changed for the same document, it can be specified to be converted into a different string.

For example, if the conversion is done in such a way that the first string in the document is converted to the last string and the last string is converted to the second string by all word units of the document, it is exchanged with the first string according to the conversion key value. You can change the sequence number of the string at the end of the string. Another method is to convert the text string into an arbitrary word other than the word included in the original text or into a text string in another document. For example, you can specify that the text string of the original text is converted to the text string of the Bible and encrypted. Depending on the conversion key value, the order of the conversion target string of the Bible can be changed and specified. It is also possible to convert the original text to a dictionary-based basis. Each character string in the original text can be designated to correspond to a word in the dictionary. The order of the designated words can be adjusted with the conversion key value. In this way, conversion between strings can be used in many different ways for encryption.

It is also possible to specify a character string conversion encryption method for one encrypted font file (encrypted font). In this case, it is possible to reuse the encrypted font file created in advance without the need to generate a font file corresponding to the encrypted document whenever the original text string is encrypted. In order to specify the string conversion encryption method for each font file, the string to be converted must be specified in advance.

The original string to be converted can be designated as a word according to the frequency of use for each language. For example, for Hangul characters, a character string to be converted can be designated for the Korean language learning vocabulary created by the Korean Language Institute. For English characters, a character string to be converted can be specified for the essential vocabulary of middle and high school. Also, the number of words to be designated as the original character string can be adjusted according to the order of frequency of use and essential vocabulary. The corresponding character string can be specified in the same way as used in encryption for each document. Various methods are possible, such as converting to a string in a specific document such as a bible or a dictionary, or converting to a hash function value.

It is also possible to mix and use the string conversion encryption method and the obfuscation encryption method through simple exchange between characters. By additionally applying an obfuscation encryption method to the converted ciphertext, the ciphertext word can be converted into an unreadable text form. For example, "Nice to meet you. This is Secure Font 2!" If the string is converted to the string "fr8759", it can be converted to unreadable text such as "q}CB@D" by applying obfuscation encryption to the converted string.

Converting one string to another string Encryption method is the method of directly converting one string to another string, and converting one string to the corresponding character in the intermediate stage, and then converting the corresponding character in the intermediate stage back to another string. It is also possible to construct a method with a step of transforming.

Intermediate conversion to match the "k" character for the ciphertext string "fr87", and "Nice to meet you" for the "k" character. If it is processed to be converted back to a string, the cipher string "fr87" can produce the same result as reproducing the original text of "Nice to meet you". This intermediate step is processed during the encryption process inside the font and does not affect the character strings of the original text and the cipher text.

In addition, encryption may be performed by mixing the encryption methods of FIGS. 2 to 7 . For example, a stronger ciphertext can be created by using a mixture of methods such as conversion between characters, multiple conversion between characters, conversion between characters and strings, and conversion between strings. Even when this mixed method is used, the original text can be reproduced and displayed only with the cipher text and font without the need to transmit separate decryption logic or conversion rules to the outside. In addition, the encryption device 110 may use an encryption method to calculate a cipher text that is difficult to decrypt.

Referring to the above-described embodiment, the encryption apparatus according to an embodiment of the present invention generates an encryption font and an encrypted text instructing to reproduce the original text or character string as a different character or string according to the encryption method.

8 shows an information set required to perform substitution in an encryption method according to an embodiment of the present invention. A set of information corresponding to the methods described with reference to FIGS. 2 to 7 will be looked at. The information set means a set of information, and may be referred to as an information pair, an information group, or the like.

The original text and the original text are included in the original text, and refer to a target to be converted by the encryption device 110 . The substitution character and the substitution string refer to a target that is a result of conversion by the encryption device 110 . A substitution condition refers to a substitution condition in multiple substitutions. The intermediate substitution condition may include a condition in which a specific character string is replaced with a single character for substitution between character strings, and a result of the substitution is re-substituted.

As shown in FIG. 8 , the encryption device 110 includes a character-to-character substitution information set 51 , a character-to-character multiple substitution information set 52 , a character-to-string substitution information set 53 , and a character string-to-character substitution information A set 54 and a substitution information set 55 in which the information set between character strings are mixed can be generated.

The information sets 51 to 55 of FIG. 8 are information generated by the encryption device 110 .

The inter-character substitution information set 51 is composed of an original character and a substituted character substituted therefor. Since this is a 1:1 substitution, there is no separate substitution condition.

The character-to-character multiple substitution information set 52 is composed of an original character, a substitution character substituted therefor, and a substitution condition. 4, when the character "e" is substituted with any one of "da/t/e", a substitution condition may be included.

The character-string substitution information set 53 is composed of an original character and a substitution character string substituted therefor. The character string-character substitution information set 54 is composed of an original character string and substitution characters substituted for the original character string.

The substitution information set 55 in which the information set between character strings is mixed is composed of an original character string, a substitution character string replacing it, and an intermediate substitution condition. The intermediate substitution condition includes a condition for an intermediate process in the process of changing the original character string into the substitution character string. As an example, the string "nice to meet you" may be replaced with the string "f24a37009b415b" or "morning". In this case, the target string may include characters included in the original string. Therefore, an intermediate process may be necessary for the substitution between strings to be performed. To replace the string "nice to meet you" with the string "f24a37009b415b", you can specify that the string "f24a37009b415b" is first replaced with the letter "B" and the letter "B" is replaced with the string "nice to meet you" again. In this case, an intermediate substitution condition is included.

Hereinafter, the detailed configuration of the encryption device and the encryption process will be described in more detail.

9 shows the configuration of an encryption device according to an embodiment of the present invention. The encryption device 110 may be implemented in one device, such as a laptop computer, a mobile phone, or a tablet. Alternatively, the encryption device 110 may perform encryption collaboratively in two or more computing devices. In this case, the encryption device 110 may refer to a system composed of a client and a server.

The encryption device 110 receives input or selection of an original text input by a user or provided as a file and a font selected by the user, and finally generates an encrypted text and an encrypted font.

The conversion code generator 111 generates a conversion code that determines the substitution encryption internal rule. The conversion code generator 111 generates a unique code value using user information and automatic generation rules.

A substitution rule generator 112 creates a substitution rule. At this time, the substitution rule generator 112 internally corresponds to each of the substitution schemes described in FIGS. 2 to 7 , “inter-character 1:1 substitution rule generator”, “inter-character multiple substitution rule generator”, “character-string It may include "interchange rule generator", "string-to-character substitution rule generator", "interstring substitution rule generator", "mixed substitution rule generator" and "substitution rule checker" as sub-components. Also, the substitution rule generator 112 may further include a “substitution rule storage” for storing substitution rules. Alternatively, the “substitution rule repository” may be configured separately from the substitution rule generator 112 . Of course, by configuring the functions provided by these sub-components into one software, the substitution rule generator 112 may provide all of the respective functions.

The text converter 113 converts and encrypts the character code of the original text using the substitution information sets (51 to 55 in FIG. 8) generated by the substitution rule generator 112.

The encrypted font generator 114 converts and encrypts the font. Encrypted font generator 114 internally supports each of the substitution methods described in FIGS. 2 to 7 "1:1 substitution cmap generator between characters", "multiple substitution GSUB generator between characters", "character-to-string substitution" GSUB generator", "string-to-character substitution GSUB generator", "string-to-character substitution GSUB generator", "mixed substitution GSUB generator" and "font converter" as sub-components. In addition, the encrypted font generator 114 may further include an "encrypted font storage" or a "font file storage" that stores an encrypted font file (encrypted font).

Alternatively, the “font file storage” may be configured separately from the encrypted font generator 114 . Of course, by configuring the functions provided by these sub-components into one software, the encryption font generator 114 may provide all of the respective functions.

Each of the components of FIG. 9 may be configured as one piece of software or hardware, or may be configured by being divided into several pieces of software and several pieces of hardware.

The process of operation in FIG. 9 is as follows.

The conversion code generator 111 of the encryption device 110 receives the font, the original text, and identification information indicating the encryption method for encrypting the text. Then, the conversion code generator 111 generates a conversion code to be used for converting one or more characters of the original text according to an encryption method indicated by the identification information or a character code to be replaced with a character string code.

The substitution rule generator 112 of the encryption device 110 generates a substitution information set including a substitution rule corresponding to the conversion code.

The text converter 113 of the encryption device 110 converts one or more character codes of the original text according to the substitution rule to generate the encrypted text.

The encryption font generator 114 of the encryption device 110 converts and encrypts the character code character-pattern mapping information (cmap) and transformation and ligature information (GSUB) or design information (glyf) of the font in response to the substitution information set do. The result is an encrypted font, that is, an encrypted font.

10 shows an encryption process of a secure font according to an embodiment of the present invention.

The process shown in FIG. 10 may be commonly applied to encryption of multiple substitutions (inter-character, character-string, character-to-string substitution) of the document previously described in the embodiments of FIGS. 2 to 7 . The encryption process is performed in the encryption device 110 that performs encryption. In another embodiment, the encryption device 110 may indicate one system including a terminal device and a server device.

The user inputs text or selects text to be encrypted, and designates a font to be used for outputting the encrypted text (S61).

Next, the user selects an encryption method (S62). The multi-character substitution encryption shown in the embodiment of FIGS. 2 to 4 , the character-string substitution encryption shown in the embodiment of FIG. 5 , the string-character substitution encryption shown in the embodiment of FIG. 6 , and the embodiment of FIG. 7 You can select the substitution encryption between strings, which we looked at in . Alternatively, a mixed encryption method may be selected to include two or more encryption methods among the various encryption methods described above.

In this case, the user may designate that the encryption device automatically selects an encryption method. In this case, the encryption device randomly selects a specific encryption method from among character-to-character multiple substitution encryption, character-to-string substitution encryption, string-to-character substitution encryption, string-to-character substitution encryption, and mixed encryption methods, or according to the characteristics of the characters in the document. , or depending on the number of characters in the document.

Thereafter, the encryption device 110 generates a conversion code that determines the substitution encryption internal rule (S63). The conversion code is generated by the conversion code generator 111 shown in FIG. 9 . The conversion code generator 111 generates a unique code value using user information and automatic generation rules. That is, the conversion code may be input by a user from the outside or may be randomly generated by the conversion code generator 111 .

In this case, the encryption device 110 may provide an interface for the user to generate a conversion code. In this case, when the user inputs a desired string, the conversion code generator 111 checks whether the user-specified string is the only code within the system. If the code is not unique, the conversion code generator 111 may generate a unique conversion code value by adding the code value generated by the automatic generation rule to the user-specified string.

When the conversion code is generated, the substitution rule generator 112 generates a substitution rule ( S64 ). 9, the substitution rule generator 112 sets each substitution rule according to the type of substitution rule (character-to-character 1:1, character-to-character multiple, character-string, character-string-character, character-string-new character string substitution, etc.) You can include a separate generator that creates it. Alternatively, the substitution rule generator 112 may generate a substitution rule in response to various substitution rules.

According to the substitution rule, one or two or more specific steps from S64-1 to S64-4 may be selected and performed.

Look at step S64-1. The substitution rule generator 112 (or a separately configured 1:1 substitution rule generator between characters) uses a conversion code to designate a different character code corresponding to each character code in the text and replaces them in a way that they are exchanged with each other. When the substitution is completed, a set of substitution information between characters is created and stored. In this case, the inter-character substitution information set 51 of FIG. 8 is generated as an embodiment.

Looking in more detail, the substitution rule generator 112 (or a separately configured 1:1 substitution rule generator) uses a conversion code to designate a different character code corresponding to each of all character codes included in the font and exchange them with each other. method can be replaced. Then, when the substitution is completed, a set of substitution information between characters is generated and stored.

Meanwhile, unlike the above-described example, the substitution rule generator 112 (or a separately configured 1:1 substitution rule generator between characters) may omit generation of a 1:1 substitution rule between characters. When generation of the 1:1 substitution rule between characters is omitted, the character substitution information set may not be generated.

Look at step S64-2. The substitution rule generator 112 (or a separately configured multiple substitution rule generator between characters, a character-string substitution rule generator, a string-character substitution rule generator, a character-string substitution rule generator, a mixed substitution rule generator) uses a conversion code to A character-to-character substitution information set, a character-to-character substitution information set, and a character-string-to-character substitution information set are generated.

In one embodiment, when the user or the encryption device 110 selects the "multiple substitution between characters" method automatically or by setting, the substitution rule generator 112 (or the separately configured multiple substitution rule generator between characters) is Create multiple permutation information sets. In this case, the multi-character substitution information set 52 of FIG. 8 is generated as an embodiment.

In more detail, the encryption device 110 selects a character code to be replaced multiple among the character codes in the text by using the conversion code, designates a new replacement character code corresponding to the selected character code, and replaces information including condition information to be replaced. create a set In order for multiple substitutions to be performed between characters, each pair of substitutions needs a condition to be executed. For example, a condition is required to specify that the character "A" is replaced with "A" or "K". The condition under which the first permutation pair is executed and the condition under which the second permutation pair is executed may be configured differently.

In one embodiment, when the user or the encryption device 110 selects “character-string substitution” automatically or by setting, the substitution rule generator 112 (or a separately configured character-string substitution rule generator) generates characters and character strings Creates a replacement information set between A character code to be replaced with a character string among character codes in the text is selected using the conversion code, and a new character string corresponding to the selected character code is designated. As the target string, a result value of a hash function for the original character or a string obtained by transforming the hash result value may be used. As the target string, both an obfuscated string and a normal readable string can be used.

For example, the character "A" can be replaced with the string "ab0739cf3a81" or the string "hello". However, the encryption device 110 or the substitution rule generator 112 may control the substitution process so that the original character is not included in the target string. If the target string contains the original character, it can be replaced with another character.

In this case, the character-string substitution information set 53 of FIG. 8 is generated as an embodiment.

In an embodiment, when the user or the encryption device 110 selects “string-to-character substitution” automatically or by setting, the substitution rule generator 112 (or a separately configured character-string-to-character substitution rule generator) selects the character string and the character. Creates a replacement information set between The encryption device 110 selects an original character string to be replaced with a single character from among the character strings in the text by using the conversion code, and designates a new single character corresponding to the selected character string. For example, the string "Nice to meet you" can be replaced with the letter "A". The target character can be specified as a character included in the original string.

The generated character string-character substitution information set 54 of FIG. 8 is exemplified as an embodiment.

In one embodiment, when the user or the encryption device 110 selects "substitution between strings" automatically or by setting, the substitution rule generator 112 (or a separately configured substitution rule generator between character strings) ' provides a set of substitution information between character strings create Select the original character string to be replaced with another new character string among the character strings in the text using the conversion code, and designate a new character string corresponding to the selected character string. As the target string, a result value of a hash function on the original string or a modified string may be used.

As the target string, both an obfuscated string and a normal readable string can be used. For example, you can replace the string "nice to meet you" with the string "f24a37009b415b" or "morning". The target string may contain characters contained in the source string. Intermediate steps may be required for substitutions between strings to be performed. Encryption device 110 first replaces the string "Nice to meet you" with the character "B" to replace the string "Nice to meet you" with the string "f24a37009b415b" can

As an embodiment, the replacement information set 55 in which the information set between character strings of FIG. 8 is mixed as generated at this time.

In addition, in one embodiment, when the user or the encryption device 110 selects "mixed substitution" automatically or by setting, the substitution rule generator 112 (or a separately configured mixed substitution rule generator) provides a multi-character substitution information set ( 52 in FIG. 8), a character-string substitution information set (53 in FIG. 8), a character string-character substitution information set (54 in FIG. 8), a substitution information set in which the character-string information set is mixed (55 in FIG. 8) create A conversion code is used to select which substitution rule to apply to each sentence, and a substitution information set is generated for the corresponding sentence using the selected substitution rule generator.

When the substitution operation is completed, the substitution rule generator 112 (or a separately configured substitution rule checker) generates a character-to-character substitution information set and multiple substitution information set, a character-to-string substitution information set, a character string-to-character substitution information set, and a character string. Check whether there is an error in the liver replacement information set.

In an embodiment, the substitution rule generator 112 (or a separately configured substitution rule checker) may check for errors in 1:1 substitution pairs between characters. At this time, it is determined whether one original character is designated to be substituted with two or more corresponding characters in a 1:1 substitution pair between characters or whether two or more of the original characters are designated to be substituted with one corresponding character. In this case, since an error has occurred, the substitution rule generator 112 regenerates a 1:1 substitution pair between characters.

Similarly, the substitution rule generator 112 (or a separately configured substitution rule checker) determines as an error when some of the multiple substitution target characters among multiple substitution pairs are re-designated as the original characters. And the substitution rule generator 112 regenerates multiple substitution pairs.

The substitution rule generator 112 (or a separately configured substitution rule checker) determines a collision error when the original character is included in the target substitution string or included in the target substitution string of another original character among the character-string substitution pairs. And the substitution rule generator 112 generates a substitution pair again.

The substitution rule generator 112 (or a separately configured substitution rule checker) determines a collision error when a target substitution character is designated as a duplicate among the character string-character substitution pair. And the substitution rule generator 112 generates a substitution pair again.

The substitution rule generator 112 (or a separately configured substitution rule checker) determines as a collision error when the original character string is included in the target corresponding character string or other target character string among the substitution pairs between the character strings. And the substitution rule generator 112 generates a substitution pair again.

In addition, the substitution rule generator 112 (or a separately configured substitution rule checker) checks whether a conflict between each set of substitution information does not occur when a mixed substitution rule is used.

If there is no error in the substitution rule, the substitution rule generator 112 stores the substitution rule in the substitution rule storage (S64-4). In the substitution rule, one substitution rule is stored for each conversion code.

Next, the text converter 113 of the encryption device 110 converts the character code of the text by using the substitution information sets (51 to 55 in FIG. 8) generated by the substitution rule generator 112 (S65) .

In one embodiment, the text converter 113 searches for the original characters of the 1:1 substitution information set (51 of FIG. 8) between characters in the text and replaces them with corresponding characters.

In one embodiment, the text converter 113 searches the text for the substitution condition of the multiple substitution information set (52 in FIG. 8), searches for the original character of the multiple substitution information set within the searched string, and replaces the original character of the multiple substitution information set with the corresponding substitution character.

In one embodiment, the text converter 113 searches the text for the original characters of the character-string substitution information set (53 in FIG. 8 ) and replaces them with the corresponding character string.

In one embodiment, the text converter 113 searches the text for the original character string of the character string-character substitution information set (54 in FIG. 8) and replaces the text with the corresponding character.

In one embodiment, the text converter 113 searches the text for the original character string of the substitution information set between character strings (55 in FIG. 8) and replaces the original character string with the corresponding character string.

In an embodiment, the text converter 113 performs a batch substitution with a character or string corresponding to each substitution pair in the case of a mixed substitution.

When the text conversion is completed, the encryption font generator 114 of the encryption device 110 converts and encrypts the font (S66).

A detailed look at the font conversion and encryption steps of the encryption font generator 114 are as follows.

As described in step S66-1, the cipher font generator 114 (or a separately configured 1:1 substitution cmap generator between characters) converts the cmap of the font using the substitution information set (51 in FIG. 8) between characters and Encrypt the font. In cmap, mapping information for all character codes and glyphs in the font is stored. Character designs (glyphs) are stored in the glyf table for TTF fonts and in the CFF table for OTF fonts. Each character in the character-to-character substitution information set and its corresponding character are found in the character code of cmap, and the glyphs for the character codes are exchanged by exchanging the numbers of the character designs for the character codes.

In an embodiment, when there is no 1:1 replacement information set between characters (51 of FIG. 8 ), the conversion process of cmap may be omitted.

As described in step S66-2, the cipher font generator 114 (or a separately configured multi-character substitution GSUB generator, character-string substitution GSUB generator, character-string-character substitution GSUB generator, character-string substitution GSUB generator, compatible The substitution GSUB generator) generates a character-to-character substitution GSUB, a character-to-character substitution GSUB, a character-string-to-character substitution GSUB, and a character string-to-character substitution GSUB using the substitution information set (52 to 55 in FIG. 8).

In one embodiment, the cryptographic font generator 114 (or a separately configured multi-substitution GSUB generator between characters) converts the GSUB of the font and encrypts the font using the set of substitution information between characters. GSUB defines additional information required for various types and transformations of characters. Ligature information for combinations between specific characters, information about transformations between characters, and the like are included.

The cipher font generator 114 (or a separately configured inter-character multi-substitution GSUB generator) adds character-to-character multiple substitution information to the GSUB. In the case of multiple substitutions, a condition under which the substitution is to be executed (refer to 52 in FIG. 8) is required, and information on the conditions under which the substitution pair is to be executed is also added to the GSUB.

For example, the cipher font generator 114 (or a separately configured inter-character multi-substitution GSUB generator) replaces “A” with “A” and replaces “A” with “A” when the character “A” composes the “Horizontal” character string and replaces the “Bag” string with You can specify substitution with "K" when configuring. At this time, "the number of streets" becomes an execution condition for replacing "A" with "A", and "Bag" becomes a condition for replacing "A" with "K".

The cipher font generator 114 (or a separately configured character-string substitution GSUB generator) converts the GSUB of the font and encrypts the font by using the character-string substitution information set (53 in FIG. 8). In addition, in this process, substitution information between a character and a character string is added to the GSUB, and a character design can be designated to be displayed for the character string in the substitution information set.

For example, if the cipher font generator 114 (or a separately configured character-to-string substitution GSUB generator) replaces the character with the character string “ab0739cf3a81”, specify that the design of the character “A” be displayed for the character string “ab0739cf3a81”. can

The encryption font generator 114 (or a separately configured character string-character substitution GSUB generator) converts the GSUB of the font and encrypts the font by using the character string-character substitution information set (54 in FIG. 8). The cipher font generator 114 (or a separately configured character string-to-character substitution GSUB generator) adds substitution information between character strings and characters to the GSUB and specifies that character strings are displayed for characters in the substitution information set.

For example, the cipher font generator 114 (or a separately constructed string-to-character substitution GSUB generator) can specify that the string "Nice to meet you" be displayed for the letter "A" if the string "Nice to meet you" is replaced by the letter "A". can

The cipher font generator 114 (or a separately configured substitution GSUB generator between character strings) converts the GSUB of the font and encrypts the font by using the substitution information set (55 in FIG. 8) between character strings. The cipher font generator 114 (or a separately constructed substitution between character strings GSUB generator) adds substitution information between character strings and character strings to the GSUB, and designates character strings to be displayed for character strings in the substitution information set.

For example, if the cipher font generator 114 (or a separately constructed inter-string substitution GSUB generator) replaces the string "nice to meet you" with the string "f24a37009b415b", specify that the string "nice to meet you" is displayed for the string "f24a37009b415b". . In case of substitution between character strings, an intermediate process may be required to perform the substitution, and information about the intermediate process is also added to the GSUB.

For example, if the cipher font generator 114 (or a separately constructed inter-string substitution GSUB generator) replaces the string "nice to meet you" with the string "f24a37009b415b", then the string "f24a37009b415b" specifies that the character "B" is displayed and " You can specify that the "B" character be displayed again as a "nice to meet you" string.

In addition, the cipher font generator 114 (or a separately configured mixed substitution GSUB generator) includes a multi-character multiple substitution information set (52 in FIG. 8), a character-to-string substitution information set (53 in FIG. 8), and a character string-to-character substitution The GSUB of the font is converted and encrypted using the information set (54 in Fig. 8) and the replacement information set (55 in Fig. 8) in which the information set between character strings is mixed. The cryptographic font generator 114 (or a separately configured mixed substitution GSUB generator) converts and encrypts the GSUB using the corresponding GSUB generator according to the type of the substitution information set.

The above-described cryptographic font generator 114 and text converter 113 may perform inverse substitution with each other.

Next, if both cmap and GSUB information, which are font internal information, are changed, the encrypted font generator 114 creates a new encrypted font file including the changed information as in step S66-3.

And when the font file is normally generated, the encrypted font generator 114 stores the encrypted font file in the font file storage as in step S66-4. In the font file, one font file is stored per conversion code.

Thereafter, the encrypted font file and the encrypted text document may be opened again in the corresponding encryption device 110 , or may be opened after being transmitted to another device ( 120 in FIG. 1 ).

In this case, the devices 110 and 120 to open this document apply the font converted and encrypted by the encryption font generator 114 to the text document converted and encrypted by the text converter 113 of the encryption device 110 ( S67) It is possible to check the contents of the original text by restoring the text without a separate decoding process.

In addition, when there is only encrypted text and no font, the text is not converted to the original text, so the security of the text can be improved.

11 to 14 show examples of encryption and restoration according to various encryption methods of the present invention. Abg points to the font file. Abg "original font" means the original font, and "encrypted font" means the encrypted font. And the arrow marked with enc indicates the encryption process.

11 is a diagram illustrating an encryption and restoration process of multiple substitution between characters according to an embodiment of the present invention. Reference is made to the contents previously described with reference to FIG. 4 . The steps of FIG. 10 are also indicated as corresponding processes.

When text input and font selection of S61 to S62 and an encryption method (1:N multiple mapping) are selected, a conversion code is generated with the conversion code generator 111 for some characters, and also some characters (for example, "multi") character), the substitution rule generator 112 (or a separately configured multiple substitution rule generator between characters) creates a rule for substituting the corresponding character (“a”) with “e” or “l” (S63, S64) .

And the text converter 113 encrypts the text according to the substitution rule (S65). And the encrypted font generator 114 (or the multi-character substitution GSUB generator) encrypts the designated font (S66).

Here, for characters that do not correspond to multiple substitutions, the substitution rule generator 112 (or a 1:1 substitution rule generator between characters configured separately) creates a 1:1 substitution rule between characters, and, accordingly, the cipher font generator 114 (or a separately configured 1:1 substitution cmap generator between characters) can generate 1:1 substitution cmap between characters.

When the generated encrypted font is applied to the encrypted text, the original text is restored (S67).

12 is a diagram illustrating an encryption and restoration process of character-to-string substitution according to an embodiment of the present invention. Reference is made to the contents previously described with reference to FIG. 5 . The steps of FIG. 10 are also indicated as corresponding processes.

If you select the text input and font selection and encryption method (character: string mapping, one character is mapped to a character string consisting of m characters) of S61~S65, specific characters (e.g. "phone", "t") character), the substitution rule generator 112 (or a separately configured character-string substitution rule generator) generates a character string corresponding to each character as a substitution rule. And the text converter 113 encrypts each character according to the substitution rule.

And the encrypted font generator 114 (or the character-string substitution GSUB generator) encrypts the designated font (S66). When the generated encrypted font is applied to the encrypted text, the original text is restored (S67).

13 is a diagram showing an encryption and restoration process of character string-character substitution according to an embodiment of the present invention. Reference is made to the contents previously described with reference to FIG. 6 . The steps of FIG. 10 are also indicated as corresponding processes.

When text input and font selection of S61 to S65 and the encryption method (string: character mapping, a method in which m characters are mapped to a character string consisting of one character) are selected, the substitution rule generator 112 (or separately) for a specific character string The configured character string-character substitution rule generator) creates a character string corresponding to each character as a substitution rule. And the text converter 113 encrypts the corresponding character string according to the substitution rule.

And the encrypted font generator 114 (or the character string-character substitution GSUB generator) encrypts the designated font (S66).

When the generated encrypted font is applied to the encrypted text, the original text is restored (S67).

14 is a diagram showing an encryption and restoration process of substitution between character strings according to an embodiment of the present invention. Reference is made to the contents previously described in FIG. 7 . The steps of FIG. 10 are also indicated as corresponding processes.

When the text input and font selection and encryption method of S61 to S65 are selected (string: mapping between strings, a method in which a string consisting of m characters is mapped to a string consisting of n characters), a substitution rule generator (112 ) (or a separately configured substitution rule generator between character strings) creates a character string corresponding to each character as a substitution rule. And the text converter 113 encrypts the corresponding character string according to the substitution rule (S65).

And the encrypted font generator 114 (or the string-string substitution GSUB generator) encrypts the designated font (S66).

When the generated encrypted font is applied to the encrypted text, the original text is restored (S67).

15 shows a process of reconstructing and displaying the encrypted text according to an embodiment of the present invention.

The encryption device 110 generates and stores the encrypted text and the encrypted font as described above. Alternatively, the stored encrypted text and encrypted font are transmitted to the server so that other devices can check them (S71).

Then, the encrypted text is transmitted to the recovery device 120 through mail or a website, or the recovery device 120 accesses the encrypted text (S72).

Thereafter, the restoration device 120 requests the encrypted font from the server (S73). Then, the original text is restored by applying the encrypted font received by the restoration device 120 to the encrypted text (S74).

The encrypted text and the encrypted font may be transmitted to the restoration apparatus 120 together according to a method previously agreed between the encryption apparatus 110 and the restoration apparatus 120 . This is a case in which the restoration apparatus 120 authenticates that it has the authority to access the corresponding document as an embodiment.

That is, in the decryption process of FIG. 15 , the restoration apparatus 120 obtains the encrypted text and an encrypted font corresponding to the encrypted text (S71 to S73) and the restoration apparatus 120 encrypts the encrypted text by applying the encrypted font to the encrypted text. and displaying the text including the second character displayed differently from the first character of the encrypted text before the font is applied (S74).

If the encrypted font is not applied, the letter "A" in the encrypted text is displayed as "A" as it is. However, when an encrypted font is applied, the letter "A" in the encrypted text is displayed differently, such as "Ha" or "Hello". This also applies when the first character is a character string.

The embodiment of FIG. 15 will be described in more detail.

When the restoration device 120 displays the cipher text using a web browser, the cipher text and the cipher text are transmitted and displayed together with the web browser of the restoration device 120 device.

For convenience of explanation, taking the case of the blog system as an example, when a blog user (administrator) writes and saves an original text requiring protection, the text of the original text is encrypted at the time the document is saved, and an encrypted font is created at the same time ( S71).

Meanwhile, when a blog visitor (accessor) accesses the corresponding blog page, an HTML document including encrypted text is delivered to the visitor's web browser (S72). The web browser analyzes the HTML document content, checks the font information required in the HTML document, and requests the corresponding font from the server 300 (s73). The server that receives the font information request delivers the encrypted font generated when writing the original text to the web browser in the form of a web font. When the web browser receives the web font and applies the font to the corresponding HTML document, the content of the original text is reproduced and displayed on the screen (S74).

In this case, in order to restore and display the document, the web browser does not require any additional work other than receiving the web font and applying the font to the HTML document. In the content of the HTML document, the encrypted text is reproduced and displayed while maintaining the encrypted state.

In another embodiment, a system equipped with a text editor operates in the same manner. When the user creates a document requiring protection and presses the save button, the text in the document is encrypted and a corresponding encrypted font is generated at the same time (S71). The encryption process may be executed on the user's device or may be performed on the server 300 .

The generated encrypted font is stored in the storage of the server 300 . When the user delivers the encrypted document to another user (S72), when the recipient opens the encrypted document, the text editor of the recipient's device (restore device) confirms that the font used for the encrypted document is not on the recipient's device and checks the text editor server The system requests the corresponding font (S73). The server 300 transmits the corresponding encrypted font to the receiver's device.

The text editor of the recipient's device (restore device) downloads the corresponding encrypted font, loads the font in the document, and displays it. When the encrypted font is applied, the encrypted text is automatically displayed as the original text, but the text remains encrypted (S74).

The characteristic of the encryption method using the font is that the system uses the method of loading the font to display the characters, and just by applying the font without a separate decryption process, the contents of the original text are reproduced and displayed.

The embodiment of Fig. 15 is also applied to the process of displaying encryption and restoration of web documents.

After creating a web document and encrypting the created document together with the font, the above-described encryption and restoration process may be applied to display it on the user's screen.

The user writes the document content on the web document editing screen and designates the font to be applied to the text. As for the font, you can select general TTF and OTF fonts that can be used when writing documents such as Nanum Myeongjo, Nanum Gothic, and Rix Gothic. Any font can be used as long as it is a font that is allowed to be converted to a web font and is installed on the server.

When the document creation is completed, the user designates and stores the encryption method of the text document shown in FIGS. 10 to 14 . While text is encrypted, it creates an encrypted font with information corresponding to the text encryption method (multiple characters/character-string/string-character/string-string, etc.).

Thereafter, when the recipient (accessor) requests the encrypted web document with the web browser installed in the restoration device for the encrypted document created by the user, the web document including the encrypted text according to the process of FIG. 15 and the corresponding encrypted web The font is acquired and the content of the original text is reproduced and displayed in the web browser.

16 shows a process of restoring a ciphertext according to an embodiment of the present invention.

The method of reproducing the cipher text using the font in the restoration device 120 may work in the same manner in most operating systems using the TTF/OTF font.

The restoration device 120 does not restore the cipher text 77 to the text of the original text, but displays only the visual form with the same content as the original text using a font while maintaining the cipher text. Accordingly, the operation performed by the restoration apparatus 120 corresponds to display restoration or reproduction rather than decoding.

As the content of the ciphertext is indicated by 77, "tnoFe. ruce Sol. and as the original text 79 indicates, "Nice to meet you. This is a secure font. Hello, SecureFont!".

A ciphertext is encrypted by exchanging the front and back sides of the original text. In order to generate a font corresponding to the cipher text, multiple conversions were performed on the characters "e, o, l, ni, da" that appear repeatedly two or more times, and encryption was performed through the process S31/S32 of FIG. 4 .

If the restoration device 120 displays a character string of cipher text using a general font rather than an encrypted font, the restoration device 120 draws a character design corresponding to the character code 0x0074 for the “t” character in the font. Search in the character-glyph index mapping table (cmap) of the font and display the corresponding glyph “t” on the screen, and select the character design “n” corresponding to the character code 0x006e of the next character “n”. Find it and display it on the screen.

If there is a space among the characters, the blank character code "0x0020" is used and the space between the next character and the next character is spaced as much as the space for the corresponding character design. By repeating this process for all characters, the screen shows "tnoFe. ruce Sol.", which is part of the ciphertext indicated by 77. It is displayed in the form of ciphertext.

If multiple conversions between character codes are not supported, the ciphertext "tnoFe. ruce Sol. , StcureFont!" expressed only in form. This is different from the original text (79). In other words, if multiple transformations are not supported, the original text cannot be perfectly reproduced. This is because, during the encryption process, one and the same character (e.g. e) can be converted into various characters.

Therefore, when an encryption font capable of multiple conversion functions is applied to correspond to the cipher text and displayed on the screen, the restoration device 120 in order to express the first cipher text "tnoFe." Before searching the glyph index mapping table, search GSUB to see if there is an OpenType Feature function corresponding to the character code 0x0074. That is, the restoration apparatus 120 searches the open type feature function from the deformation and ligature information (GSUB).

If there is no search result, the restoration device 120 searches for a character design corresponding to the character code 0x0074 in the character code character-pattern mapping information (cmap) of the font and displays the converted character design "half" on the screen.

Even for the next character "n", the restoration device 120 searches the GSUB to see if the character code 0x006e is also designated as an OpenType Feature function, and whether there is an OpenType Feature function corresponding to the "tn" string, that is, the 0x0074 0x006e character code listing in the GSUB. Search. If there is no search result, the character design corresponding to the character code 0x006e of "n" is searched in the character code character-pattern mapping information (cmap), and the converted character design "A" is displayed on the screen.

By repeating this process for the letters "o", "F", and "e", the converted character designs "weep", "ni", and "da" are displayed on the screen, so that the cipher text "tnoFe." is "Nice to meet you." is displayed."

Repeat the same process for "ruce Sol.", the second sentence of the ciphertext. Repeat for "r", "u", and "c" to output the corresponding character designs "Bo", "An", and "Pawn", and then the character code 0x0065 for the letter "e" is also specified with the OpenType Feature function. Search GSUB to see if there is one. If there is no search result, search GSUB for OpenType Feature function for character code listing 0x0063 0x0065 of "ce" string including the preceding character.

If a search result specified to be converted to 0x0063 0xd2b8 for the 0x0063 0x0065 character code listing is found, the restoration device 120 finds the character design for the converted character code from the character code character-pattern mapping information (cmap) and displays it on the screen do. The converted character code 0x0063 displays the "phone" character design, and the 0xd2b8 character code displays the "t" character design. As a result, the ciphertext 'ce' is expressed as 'font' instead of 'fonda'. If the same procedure is performed for the remaining characters "S", "o", and "l", the string "So" is expressed as "I" in "Isa", and the string "ol" is a multiple of the string "So". According to the conversion result, it is converted from the basic conversion form "wet" to "negative", and then expressed as "nida", which is the result of multiple conversions for "knee", resulting in the second cipher text "ruce Sol." Also, it is possible to perfectly reproduce and display the contents of the original text with "This is a secure font."

The method of reproducing the original text on the screen in this way is possible in any operating system, web browser, or application program that supports the OpenType Feature function.

To summarize the process of FIG. 16 , the restoration apparatus 120 searches for an open type feature function corresponding to the first character of the encrypted text from the deformation and ligature information (GSUB). And when the function is found, as shown in S63 to S67 of FIG. 11 , the restoration device 120 converts the character design for the character code of the second character that has been converted to the first character to the character code character-pattern mapping information (cmap) Search and display in Alternatively, when a function is searched, as shown in S67 of FIG. 13 , the restoration device 120 searches the character code for the character code of the second string that was converted to the first character from the character code character-pattern mapping information (cmap). to indicate

When the function is not found, the restoration apparatus 120 searches for and displays a character design corresponding to the character code of the first character from the character code character-pattern mapping information cmap.

Here, the second character and the second character string are components for reproducing the content included in the original text.

17 shows a process of recovering a ciphertext according to another embodiment of the present invention.

17 shows a process of restoring (reproducing) an encrypted text by converting one character string into another character string in the restoration device 120 .

16, the method of reproducing the cipher text using the font in the restoration apparatus 120 works the same in most operating systems using the TTF/OTF font. The following description describes a method of reproducing the original text form in the receiving device when one character string is converted into another character string and encrypted.

Rather than decrypting the cipher text into the text of the original text, it corresponds to restoration or reproduction because only the visual form is displayed with the same content as the original text while the cipher text is maintained.

If the content of the cipher text is "fr87" and the original text is "Nice to meet you", if a character string is displayed using a normal font, the system will generate a character design corresponding to the character code 0x0066 for the character "f" in the font. Search in the code letter-pattern mapping information (cmap) and display the corresponding glyph “f” on the screen, and find the character design “r” corresponding to the character code 0x0072 of the next character “r” on the screen will be displayed in By repeating this process for all characters, the cipher text string "fr87" is displayed on the screen.

When the encryption font corresponding to the cipher text is applied and displayed on the screen, the system detects the OpenType Feature function corresponding to the character code 0x0066 before searching the character code character-pattern mapping information (cmap) for the “f” character in the encrypted font. Search in the transformation and ligature information (GSUB) to see if there are any. If there is no search result, the character design corresponding to the character code 0x0066 is searched in the character code character-pattern mapping information (cmap) of the font, and the corresponding character design 'f' is displayed on the screen. The character code 0x0072 of the next character "r" is also searched in the transformation and ligature information (GSUB) to see if there is one designated as an OpenType Feature function, and whether there is an OpenType Feature function corresponding to the "fr" string, i.e., the 0x0066 0x0072 character code listing. Search in information (GSUB). If there is no search result, the character design corresponding to the character code 0x0072 of "r" is searched in the character code character-pattern mapping information (cmap) and the corresponding character design "r" is displayed on the screen. Repeat this process for the "8" character. The character code 0x0037 for the last character "7" is also searched in the transformation and ligature information (GSUB) to see if the OpenType Feature function is specified.

If there is no search result, search for the OpenType Feature function for the character code list "0x0066 0x0072 0x0038 0x0037" of the string "fr87" in the transformation and ligature information (GSUB).

As a result of the search, if the specified to be converted to "0xbc18 0xac11 0xc2b5 0xb2c8 0xb2e4" for the "0x0066 0x0072 0x0038 0x0037" character code listing is found, the character design for the converted character code is found in the character code character-pattern mapping information (cmap) and displayed on the screen displayed on The converted character code 0xbc18 is "half" character design, 0xac11 character code is "A" character design, 0xc2b5 character code is "Wet" character design, 0xb2c8 character code is "Ni" character design, and 0xb2e4 character code is "Da" character display the drawing As a result, the password string "fr87" is displayed as a list of character designs corresponding to the "Nice to meet you" string on the screen, and the string maintains the encrypted state "fr87".

The method of reproducing the original text on the screen in this way is possible in any operating system, web browser, or application program that supports the OpenType Feature function.

17 is summarized as follows.

The restoration apparatus 120 searches for an open type feature function corresponding to a character code constituting the first string of the encrypted text from the deformation and ligature information (GSUB).

When the function is found, as shown in S67 of FIG. 12 , the restoration device 120 searches for a character design corresponding to the character code of the second character that has been converted into the first character string from the character code character-pattern mapping information cmap to indicate

Alternatively, as shown in S67 of FIG. 14 , the restoration device 120 searches for and displays a character design corresponding to the character code of the second character string that has been converted into the first character string from the character code character-pattern mapping information cmap.

Here, the second character and the second character string are components for reproducing the content included in the original text.

18 shows the configuration of an encryption system according to an embodiment of the present invention. The configuration of the encryption system 500 is based on the configuration of the encryption device of FIG. 9 . The arrow shows the process of encryption, which was previously presented in FIG. 9 and the related description.

The encryption system is a system configured with an encryption device as an embodiment. Alternatively, the encryption system is a system including an encryption device and a server as an embodiment.

That is, since the encryption operation may be performed in one device or between the encryption device and the server, the configuration of FIG. 18 is referred to as an encryption system. Accordingly, the configuration of FIG. 18 may be implemented in one device, or two or more devices include each component, and the encryption operation may be performed cooperatively in a plurality of devices.

The controller 501 receives text input or uploaded by the user and a font selected by the user. The controller 501 transmits the input information to the conversion code generator 511, and the conversion code generator 511 generates a conversion code that determines the substitution encryption internal rule. This is the same as previously discussed.

The substitution rule generator 512 replaces the description of the substitution rule generator 112 of the encryption device 110 described above.

The substitution rule generator 512 internally includes a 1:1 substitution rule generator 512a between characters, a multiple substitution rule generator 512b between characters, and a character-string corresponding to each substitution scheme described in FIGS. 2 to 7 . Substitution rule generator 512c, string-character substitution rule generator 512d, character-string substitution rule generator 512e, mixed substitution rule generator 512f, and substitution rule checker 512g may be included as sub-components. .

The substitution rule generator 512 may optionally include a 1:1 substitution rule generator 512a between characters.

In the configuration diagram of FIG. 18 , the substitution rule storage 512s is disposed outside the substitution rule generator 512 , but the present invention is not limited thereto. can

The substitution rule generator 512 may generate a substitution rule and store substitution information sets (51 to 55 in FIG. 8 ) including the substitution rule storage 512s.

Then, the text converter 513 converts the character code of the original text using the substitution information sets (51 to 55 in FIG. 8) generated by the substitution rule generator 112 and encrypts the character code.

On the other hand, the encrypted font generator 514 converts and encrypts the font. It replaces the description of the encryption font generator 114 of the encryption device 110 described above.

Encrypted font generator 514 internally supports 1:1 substitution cmap generator 514a between characters, multiple substitution GSUB generator 514b between characters that support each substitution method described in FIGS. 2 to 7, character-string It may include a substitution GSUB generator 514c, a character string-to-character substitution GSUB generator 514d, a character-string substitution GSUB generator 514e, a mixed substitution GSUB generator 514f, and a font converter 514g as sub-components.

In addition, the encrypted font generator 514 may further include a font storage (or font file storage) 514a for storing the encrypted font file.

In the configuration diagram of FIG. 18, the font file storage 514s is disposed outside the encrypted font generator 514, but the present invention is not limited thereto, and the font file storage 514s is disposed within the encrypted font generator 514. can

When a font/text is input in the encryption system 500 , a converted encrypted font and a converted encrypted text are calculated through an encryption process. It may be stored in the system, or encrypted text and encrypted fonts may be transmitted to the external device upon request of the external device.

In summary, the configuration of the device or system for performing encryption as shown in FIGS. 9 and 18 is as follows.

The controller 501 inputs the font, the original text, and identification information indicating the encryption method for encrypting the text to the conversion code generator 511 (111 in FIG. 9).

In addition, the conversion code generator 511 ( 111 of FIG. 9 ) generates a conversion code corresponding to a character code or a character string code to be replaced according to an encryption method indicated by identification information for one or more characters of the original text. Here, preferably, one conversion code may be generated. However, the present invention is not limited thereto, and one or more, for example, two or three conversion codes may be generated.

And the substitution rule generator 512 (112 of FIG. 9) generates a substitution information set including a substitution rule corresponding to the conversion code.

In addition, the text converter 513 (113 of FIG. 9) converts one or more character codes of the original text according to the substitution rule to generate the encrypted text.

In addition, the cipher font generator 514 (114 in FIG. 9) converts and encrypts the character code character-design mapping information (cmap) and transformation and ligature information (GSUB) or design information (glyf) of the font in response to the substitution information set do.

Each component may be included in one encryption device 110 . In this case, the encryption device 110 may perform encryption without interaction with other devices.

Alternatively, each component may be distributed across multiple devices. For example, the controller 501, the conversion code generator 511, the substitution rule generator 512 are included in the first encryption device, and also the cipher font generator 514, the text converter 513, the substitution rule storage 512s ), the encrypted font storage 514s may be included in the second encryption device. In this case, the encryption system includes a first encryption device and a second encryption device.

19 and 20 show the configuration of an encryption system according to another embodiment of the present invention. If the substitution rule and the encryption font generated in the process of FIG. 18 are already in the encryption system 500a, the encryption system 500a of FIG. 19 includes a conversion code generator 511, a substitution rule generator 512, and an encryption font. It is also possible to generate cipher text without the generator 514 .

Accordingly, components configured with dotted lines in FIGS. 19 and 20 may be excluded from the encryption system 500a. Instead, the conversion code is secured in the encryption system 500a in advance.

As a result, the text converter 513 can encrypt the original text by using the text input by the controller 501, the conversion code stored in the encryption system 500a, and the substitution rule in the substitution rule storage 512s. As a result, the converted encrypted text is produced.

19 and 20, the encrypted font is already stored in the encryption system 500a. Accordingly, the encryption system 500a generates the encrypted text and the encrypted font in a short time without a separate replacement rule generation and encryption font generation process.

19 and 20 show the encrypted text by converting one or more character codes of the original text using the controller 501 that receives the font and the original text, the conversion code required for encrypting the text, and the replacement information set stored in the replacement rule storage. A text converter 513 that generates a cipher font that is encrypted by converting the character code character-pattern mapping information (cmap) and transformation and ligature information (GSUB) or design information (glyf) of the font corresponding to the substitution information set. Stored encrypted font storage 514s.

The substitution information set stored in the substitution rule storage 512s is the same as described above with reference to FIG. 8 .

For example, as indicated by 52, the substitution information set includes either a second character (substitution character) or a third character (substitution character) substituted corresponding to the first character (original character) constituting the original text. It may include information indicating the character of In this case, the substitution condition is also included in the substitution information set.

For example, as indicated by 53, the substitution information set includes information indicating two or more characters constituting a first character string (substitution character string) substituted in correspondence with the first character (original character) constituting the original text. may include

For example, as indicated by 54, the substitution information set indicates a fourth character (substitution character) to be substituted corresponding to a first character string (original character string) composed of two or more consecutive characters constituting the original text. may contain information.

For example, as indicated by 55, the replacement information set is replaced with a first string (original string) composed of two or more consecutive characters constituting the original text, and a second string (replacement) different from the first string string) may be included. In this case, the intermediate substitution condition of the character string is also included in the substitution information set.

The encryption method is summarized as follows.

2 to 4 and 11 is an encryption method for selecting and encrypting either the second character or the third character with respect to the first character constituting the original text. Accordingly, the substitution rule generators 112 and 512 generate information indicating any one of the second character or the third character to be substituted in response to the first character. This is an embodiment in which the permutation rule generators 112 and 512 generate permutation information sets.

In addition, the text converters 113 and 513 convert the two or more first characters of the original text by selecting one of the second character and the third character, respectively. In this case, the first character may be converted into a second character or converted into a third character randomly, or according to a position or a front and back character, or according to an order. This is an embodiment in which the text converters 113 and 513 generate encrypted text.

5 and 12 is an encryption method for selecting and encrypting a first string composed of two or more characters with respect to the first character constituting the original text. Accordingly, the substitution rule generators 112 and 512 generate information indicating two or more characters constituting the first character string to be substituted in response to the first character. This is an embodiment in which the permutation rule generators 112 and 512 generate permutation information sets.

And the text converters 113 and 513 convert the first character of the original text into the first character string. This is an embodiment in which the text converters 113 and 513 generate encrypted text.

6 and 13 are encryption methods for selecting and encrypting a first character with respect to a first string composed of two or more consecutive characters constituting the original text. Accordingly, the substitution rule generators 112 and 512 generate information indicating one character constituting the first character to be substituted in response to the first string. This is an embodiment in which the permutation rule generators 112 and 512 generate permutation information sets.

The text converters 113 and 513 convert the first character string of the original text into the first character. This is an embodiment in which the text converters 113 and 513 generate encrypted text.

7 and 14 is an encryption method for selecting and encrypting a second string that is different from the first string and at least one character with respect to a first string consisting of two or more consecutive characters constituting the original text. . Accordingly, the substitution rule generators 112 and 512 generate information indicating two or more characters constituting the second string to be substituted in response to the first string. This is an embodiment in which the permutation rule generators 112 and 512 generate permutation information sets.

The text converters 113 and 513 convert the first string of the original text into the second string. This is an embodiment in which the text converters 113 and 513 generate encrypted text.

In particular, if the various encryption methods discussed above are applied, a higher level of encryption that is difficult to infer is possible by diversifying the exchange rules between character codes. In addition, since encryption between character codes as well as character codes is possible, it becomes difficult to restore the original text from the encrypted text. In addition, four new types of character codes and character string encryption methods of multiple substitution between characters, substitution between characters and character strings, substitution between character strings and characters, and substitution between character strings, and their mixed use, improve the complexity of encryption.

Instead, since the original text can be reproduced by applying the encrypted font without a separate decryption process for the encrypted text, strong and fast encryption and confirmation of the contents are possible.

In particular, with the development of computing technology, artificial intelligence technology, and big data technology, it has become possible to easily acquire necessary information from an Internet website using an automated collection system (Bot system). Documents obtained in large quantities from the Internet are reclassified and stored using various syntax analysis programs, and are used in various places.

However, many of the information collected in such an automated collection system require copyright protection, but it is difficult to identify the copyright in a large amount of collected information, and it is more difficult to identify the source in the reclassified and stored information.

Articles written on blogs, online bulletin boards, and SNS are also reshared by unspecified people and delivered through interpersonal text message services, making it difficult to identify the source. This copyright protection issue is equally occurring not only for individuals but also for each media company that provides Internet news content services.

In particular, only when the original source of news content is recorded, delivered, and protected, news content consumers can access the original source service of the media company and consume the content, and the media company can be compensated fairly for content production.

In addition, as IoT technology develops, various devices in an individual's home and office are being connected to the Internet. Because these devices contain or have access to sensitive personal information, they require very strong safeguards.

However, some IoT devices have problems such as being able to access them with a simple password. In particular, problems such as information stored in IoT devices that are discarded after use are not encrypted or that information can be easily obtained using a program controlling the IoT device are occurring.

As such, as information technology develops, there is a growing need for a method of preventing the text documents of the author from being distributed or indiscriminately exposing information that must be protected, such as personal information, contrary to the intention of the original author.

Text-based information needs more protection because it is easy to copy and store, but the encryption method is often complicated or difficult. In addition, existing encryption techniques can only verify the text content of the original text only through a decryption process. The decrypted and reconstructed text has a limitation in having a risk of re-exposure.

When the embodiment of the present invention is applied, the restoration reproduces the encrypted original text, and the actual encrypted text is not decrypted. That is, the user sees the text in a reproduced form, but cannot reuse it by copying or the like. Accordingly, the encryption and reproduction of the text has the effect of protecting the copyright of the text.

In particular, if the embodiments of the present invention are applied to the copying, scrapping, and automatic document collection bot (web crawling) of the problematic web document in an open environment, it can be reproduced while maintaining the encrypted state. Therefore, the document protection effect is great.

When the embodiments described so far are applied, the encryption level is increased, and the text of a website and information stored in devices such as IoT can be encrypted.

That is, the conventional document security has a limitation in encryption due to the encryption of the file itself or the 1:1 single substitution for each character of the text. The encryption of the file itself cannot control the distribution of contents after decryption, and there has been a problem that a single 1:1 replacement for each character has a low level of encryption, so it can be easily decrypted.

When the complex encryption method described in this specification is applied, in particular, since the content can be reproduced only when an encrypted font (security font) and encrypted text (security text) are provided as a set, the protection effect of the content can be increased. .

Even if all components constituting the embodiment of the present invention are described as being combined or operated as one, the present invention is not necessarily limited to this embodiment, and all components may be used as one or more within the scope of the present invention. They may be selectively combined to operate. In addition, all of the components may be implemented as one independent hardware, but some or all of the components are selectively combined to perform some or all functions of the combined components in one or a plurality of hardware program modules It may be implemented as a computer program having Codes and code segments constituting the computer program can be easily deduced by those skilled in the art of the present invention. Such a computer program is stored in a computer readable storage medium (Computer Readable Media), read and executed by the computer, thereby implementing the embodiment of the present invention. The storage medium of the computer program includes a magnetic recording medium, an optical recording medium, and a storage medium including a semiconductor recording device. In addition, the computer program implementing the embodiment of the present invention includes a program module that is transmitted in real time through an external device.

It is to be understood that the foregoing embodiments are illustrative in all respects and not restrictive, and the scope of the present invention will be indicated by the appended claims rather than the foregoing detailed description. And it should be construed as being included in the scope of the present invention, as well as the meaning and scope of the claims, as well as all transformations and deformable forms derived from the equivalent concept.

110, 510, 510a: encryption device 120: recovery device
300: server

Claims (17)

A conversion code corresponding to a character code or a character string code to be replaced according to the encryption method indicated by the identification information by receiving the font, the original text, and identification information indicating the encryption method for encrypting the text, and replacing one or more characters of the original text according to the encryption method indicated by the identification information Transform code generator to generate;
a substitution rule generator for generating a substitution information set including a substitution rule corresponding to the conversion code;
a text converter for generating encrypted text by converting one or more character codes of the original text according to the substitution rule; and
An encryption device comprising an encryption font generator for converting and encrypting character code character-pattern mapping information (cmap) and transformation and ligature information (GSUB) or design information (glyf) of the font in response to the replacement information set.
According to claim 1,
The encryption method is an encryption method of selecting and encrypting either a second character or a third character with respect to the first character constituting the original text,
The substitution rule generator generates information indicating any one of a second character or a third character to be substituted in response to the first character,
The text converter converts the two or more first characters of the original text by selecting one of the second character and the third character, respectively.
According to claim 1,
The encryption method is an encryption method for selecting and encrypting a first string composed of two or more characters with respect to the first character constituting the original text,
The substitution rule generator generates information indicating two or more characters constituting the first string to be substituted in response to the first character,
The text converter converts two or more first characters of the original text into the first string.
According to claim 1,
The encryption method is an encryption method for selecting and encrypting a first character with respect to a first string consisting of two or more consecutive characters constituting the original text,
The substitution rule generator generates information indicating one character constituting the first character to be substituted in response to the first string,
The text converter converts the first character string of the original text into the first character.
According to claim 1,
The encryption method is an encryption method of selecting and encrypting a second string that is different from the first string by at least one character with respect to a first string consisting of two or more consecutive characters constituting the original text,
The substitution rule generator generates information indicating two or more characters constituting the second string to be substituted in response to the first string,
The text converter converts the first string of the original text into the second string.
According to claim 1,
The conversion code is input by the controller or is randomly generated by the conversion code generator.
According to claim 1,
a substitution rule storage for storing the substitution information set; and
An encryption device, further comprising a cryptographic font storage for storing the cryptographic font.
The conversion code generator of the encryption device receives the font, the original text, and identification information indicating the encryption method for encrypting the text, and replaces one or more characters of the original text according to the encryption method indicated by the identification information; or generating a conversion code corresponding to the string code;
generating, by the substitution rule generator of the encryption device, a substitution information set including a substitution rule corresponding to the conversion code;
generating, by the text converter of the encryption device, an encrypted text by converting one or more character codes of the original text according to the substitution rule; and
Encrypting the encryption font generator of the encryption device by converting the character code character-design mapping information (cmap) and transformation and ligature information (GSUB) or design information (glyf) of the font in response to the replacement information set How to encrypt text.
9. The method of claim 8,
The encryption method is an encryption method of selecting and encrypting either a second character or a third character with respect to the first character constituting the original text,
The step of generating the replacement information set is
and generating, by the substitution rule generator, information indicating any one of a second character or a third character to be substituted in response to the first character,
The step of generating the encrypted text is
and converting the two or more first characters of the original text by the text converter by selecting one of the second character and the third character, respectively.
9. The method of claim 8,
The encryption method is an encryption method for selecting and encrypting a first string composed of two or more characters with respect to the first character constituting the original text,
The step of generating the replacement information set is
generating, by the substitution rule generator, information indicating two or more characters constituting the first string to be substituted corresponding to the first character,
The step of generating the encrypted text is
and converting, by the text converter, a first character of the original text into the first string.
9. The method of claim 8,
The encryption method is an encryption method for selecting and encrypting a first character with respect to a first string consisting of two or more consecutive characters constituting the original text,
The step of generating the replacement information set is
generating, by the substitution rule generator, information indicating one character constituting the first character to be substituted in response to the first string,
and converting, by the text converter, a first string of the original text into the first character.
9. The method of claim 8,
The encryption method is an encryption method of selecting and encrypting a second string that is different from the first string by at least one character with respect to a first string consisting of two or more consecutive characters constituting the original text,
The step of generating the replacement information set is
The substitution rule generator includes information indicating two or more characters constituting the second string to be substituted in response to the first string,
and converting, by the text converter, the first string of the original text into the second string.
a controller that receives fonts and original text;
a text converter that converts one or more character codes of the original text using a conversion code necessary for encrypting the text and a replacement information set stored in a replacement rule storage to generate an encrypted text; and
Encryption including an encrypted font storage in which an encrypted font is stored by converting the character code character-design mapping information (cmap) of the font and transformation and ligature information (GSUB) or design information (glyf) in response to the replacement information set Device.
14. The method of claim 13,
The substitution information set is
information indicating any one of a second character or a third character substituted for the first character constituting the original text; or
contains information indicating two or more characters constituting a first string substituted in correspondence with the first character, or
contains information indicating a fourth character to be substituted corresponding to a first string composed of two or more consecutive characters constituting the original text; or
and information indicating a second string that is substituted for the first string and is different from the first string.
obtaining, by the restoration apparatus, an encrypted text and an encrypted font corresponding to the encrypted text; and
Displaying text including a second character displayed differently from the first character of the encrypted text before the encrypted font is applied by applying the encrypted font to the encrypted text; .
16. The method of claim 15,
The restoration apparatus further comprises the step of retrieving an open type feature function corresponding to the first character of the encrypted text in transformation and ligature information (GSUB),
When the function is found, the character code for the character code of the second character that was converted to the first character or the character code of the second string that was converted to the first character is retrieved from the character code character-design mapping information (cmap) and displayed step; or
If the function is not found, the character code character-pattern mapping information (cmap) for a character design corresponding to the character code of the first character, including any one of the steps of searching and displaying Way.
16. The method of claim 15,
retrieving, by the restoration apparatus, an open type feature function corresponding to a character code constituting the first string of the encrypted text in transformation and ligature information (GSUB); and
When the function is found, a character design corresponding to the character code of the second character converted to the first string or the character code of the second string converted to the first string is searched and displayed in the character code character-pattern mapping information (cmap) A method of recovering cipher text, further comprising the step of:

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