CN114091081A

CN114091081A - Subtitle file encryption and decryption method, system, storage medium and electronic equipment

Info

Publication number: CN114091081A
Application number: CN202111431014.5A
Authority: CN
Inventors: 陈钢
Original assignee: Beijing QIYI Century Science and Technology Co Ltd
Current assignee: Beijing QIYI Century Science and Technology Co Ltd
Priority date: 2021-11-29
Filing date: 2021-11-29
Publication date: 2022-02-25

Abstract

The embodiment of the invention provides a method, a system, a storage medium and an electronic device for encrypting and decrypting subtitles. The encryption method comprises the following steps: acquiring a subtitle file to be encrypted; obtaining character representation data corresponding to characters in the sentence according to the character comparison table; replacing characters in a sentence with character representation data corresponding to the characters, representing the characters in the sentence by sequence marks contained in the character representation data corresponding to the characters, and setting the arrangement positions of the sequence marks according to the arrangement positions of the characters in the sentence to obtain a sequence mark set corresponding to the sentence; and splicing the sequence mark sets into the encrypted subtitle files according to the playing time intervals of the sentences corresponding to the sequence mark sets. The invention can solve the problem that the caption stream is stolen because the caption is transmitted in the plain text.

Description

Subtitle file encryption and decryption method, system, storage medium and electronic equipment

Technical Field

The present invention relates to the technical field of subtitle security, and in particular, to a method, a system, a storage medium, and an electronic device for encrypting and decrypting a subtitle file.

Background

With the enhancement of the awareness of Digital Rights, a DRM (Digital Rights Management) system has come into play, and the DRM system can effectively protect the copyright of the played Digital video content, so as to prevent the Digital video content from being illegally copied, copied and spread, and prevent an illegal or unauthorized user from normally playing the video program.

However, when playing video with subtitles, the video stream can be protected by the DRM system, but cannot be protected by the independent subtitle stream, and most of the independent subtitle streams are transmitted in plaintext. Therefore, how to prevent the independent subtitle stream from being stolen by illegal users or unauthorized users becomes an urgent problem to be solved.

Disclosure of Invention

An object of the embodiments of the present invention is to provide a method, a system, a storage medium, and an electronic device for encrypting and decrypting a subtitle file, which can solve the problem that a subtitle stream is stolen due to the transmission of subtitles in the clear text. The specific technical scheme is as follows:

the invention provides a subtitle file encryption method, which comprises the following steps:

acquiring a subtitle file to be encrypted; the subtitle file comprises a plurality of groups of sentences with playing time interval marks; the sentence comprises one or more characters;

obtaining character representation data corresponding to characters in the sentence according to a character comparison table; the character representation data is used for representing the characters through data different from the characters, the character comparison table is used for representing the corresponding relation between the characters and the character representation data, the character representation data corresponding to different characters are different, each character representation data in the character comparison table is provided with a sequence mark set according to preset sequencing, and the sequence marks of different character representation data are different;

replacing characters in the sentence with character representation data corresponding to the characters, representing the characters in the sentence by sequence marks of the character representation data corresponding to the characters, and setting the arrangement positions of the sequence marks according to the arrangement positions of the characters in the sentence to obtain a sequence mark set corresponding to the sentence;

and splicing the sequence mark sets into encrypted subtitle files according to the playing time intervals of the sentences corresponding to the sequence mark sets.

Optionally, the generating manner of the character comparison table includes:

carrying out duplication elimination processing on the characters in the subtitle file to be encrypted to obtain duplicated characters; selecting character representation data from the first character representation data set to obtain selected character representation data; the selected character representation data are different from the de-duplicated characters, and the number of the selected character representation data is not less than the number of the de-duplicated characters; and corresponding the de-duplicated characters with the selected character representation data, so that each de-duplicated character is corresponding to at least one selected character representation data, and the character representation data corresponding to different characters are different, and generating a character comparison table.

Optionally, the generating manner of the character comparison table includes: at least one of the first and second modes:

the first mode specifically includes: acquiring a common character set and a second character representation data set; the number of character representation data in the second character representation data set is not less than the number of symbols in the common symbol set; selecting character representation data from the second character representation data set to correspond to characters in the common character set, so that each character in the common character set corresponds to at least one character representation data in the second character representation data set, and the character representation data corresponding to different characters are different, and generating a character comparison table;

the second mode specifically includes: acquiring a corresponding relation file; the corresponding relation file comprises corresponding relations of a plurality of groups of characters and character representation data, the characters in each group of corresponding relations are different from the character representation data, and the character representation data in different corresponding relations are different; and selecting the corresponding relation between the characters matched with the characters in the subtitle file to be encrypted and the character representation data from the corresponding relation file to generate a character comparison table.

Optionally, the preset ordering is determined according to an arrangement position of the character representation data in the character comparison table in the sentence, or the preset ordering is determined according to an arrangement position of the character representation data in the character comparison table.

Optionally, the method for generating character representation data specifically includes:

acquiring a character image;

generating image encoding data of the character image;

and taking the image coded data as character representation data corresponding to characters in the character image.

The invention also provides a caption file encryption system, which comprises:

the first file acquisition module is used for acquiring a subtitle file to be encrypted; the subtitle file comprises a plurality of groups of sentences with playing time interval marks; the sentence comprises one or more characters;

the character representation module is used for obtaining character representation data corresponding to the characters in the sentence according to a character comparison table; the character representation data is used for representing the characters through data different from the characters, the character comparison table is used for representing the corresponding relation between the characters and the character representation data, the character representation data corresponding to different characters are different, each character representation data in the character comparison table is provided with a sequence mark set according to preset sequencing, and the sequence marks of different character representation data are different;

a sequence mark set generation module, configured to replace a character in the sentence with character representation data corresponding to the character, represent the character in the sentence with a sequence mark included in the character representation data corresponding to the character, and set an arrangement position of each sequence mark according to an arrangement position of the character in the sentence, so as to obtain a sequence mark set corresponding to the sentence;

and the encryption module is used for splicing the sequence mark sets into encrypted subtitle files according to the playing time intervals of the sentences corresponding to the sequence mark sets.

The invention also provides a subtitle file decryption method, which comprises the following steps:

acquiring a subtitle file to be decrypted; the subtitle file to be decrypted comprises a plurality of sequence mark sets spliced according to the sequence of the playing time interval; the sequence mark set comprises a plurality of sequence marks with arrangement sequences, and the arrangement sequences of the sequence marks represent the arrangement sequences of characters in the sentences of the subtitle files;

acquiring a sequence mark set corresponding to a playing time interval from the subtitle file to be decrypted to obtain a sequence mark set;

representing the sequence mark set by using character representation data with sequence marks set according to preset sequencing, and setting the arrangement positions of the character representation data according to the arrangement positions of the sequence marks in the sequence mark set to obtain a character representation data set corresponding to the sequence mark set; the character representation data is used for representing the character through data different from the character;

performing character conversion on the character representation data in the character representation data set according to a character comparison table to obtain characters corresponding to the playing time period; the character comparison table is used for representing the corresponding relation between characters and character representation data, and the character representation data corresponding to different characters are different;

and sequencing the characters according to the arrangement sequence of the character representation data in the character representation data set to obtain the sentence corresponding to the playing time interval.

The invention also provides a caption file decryption system, which comprises:

the second file acquisition module is used for acquiring a subtitle file to be decrypted; the subtitle file to be decrypted comprises a plurality of sequence mark sets spliced according to the sequence of the playing time interval; the sequence mark set comprises a plurality of sequence marks with arrangement sequences, and the arrangement sequences of the sequence marks represent the arrangement sequences of characters in the sentences of the subtitle files;

a set obtaining module, configured to obtain a sequence tag set corresponding to a playing time period from the subtitle file to be decrypted, so as to obtain a sequence tag set;

the character representation data set generation module is used for representing the sequence mark set by character representation data with sequence marks set according to preset sequencing, and setting the arrangement positions of the character representation data according to the arrangement positions of the sequence marks in the sequence mark set to obtain a character representation data set corresponding to the sequence mark set; the character representation data is used for representing the character through data different from the character;

the character conversion module is used for performing character conversion on the character representation data in the character representation data set according to a character comparison table to obtain characters corresponding to the playing time period; the character comparison table is used for representing the corresponding relation between characters and character representation data, and the character representation data corresponding to different characters are different;

and the decryption module is used for sequencing the characters according to the arrangement sequence of the character representation data in the character representation data set to obtain the sentence corresponding to the playing time interval.

The present invention also provides a computer-readable storage medium having stored thereon a program that, when executed by a processor, implements the above-described subtitle file encryption method and/or the above-described subtitle file decryption method.

The present invention also provides an electronic device comprising:

at least one processor, and at least one memory, bus connected with the processor;

the processor and the memory complete mutual communication through the bus; the processor is used for calling the program instructions in the memory to execute the subtitle file encryption method and/or the subtitle file decryption method.

According to the method, the system, the storage medium and the electronic equipment for encrypting and decrypting the subtitle, characters are converted into character representation data through the character comparison table, so that from the perspective of a client, UTF8 codes of the characters in the subtitle file are not present in a network or a memory, but the characters represent the data, and the protection of the characters in the subtitle file is enhanced; and the character representation data are all corresponding to sequence marks, and the encrypted subtitle file obtained by representing the character representation data by the sequence marks further increases the difficulty of cracking characters in the subtitle file by illegal users or unauthorized users.

Of course, it is not necessary for any product or method of practicing the invention to achieve all of the above-described advantages at the same time.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of a subtitle file encryption method according to an embodiment of the present invention;

fig. 2 is a structural diagram of a subtitle file encryption system according to an embodiment of the present invention;

fig. 3 is a flowchart of a subtitle file decryption method according to an embodiment of the present invention;

fig. 4 is a structural diagram of a subtitle file decryption system according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a subtitle file encryption method, as shown in fig. 1, the method comprises:

step 101: and acquiring a subtitle file to be encrypted. The subtitle file comprises a plurality of groups of sentences with playing time interval marks; a sentence includes one or more characters.

In video playing, the time interval of playing voice is usually accompanied by subtitles, and the video accompanied by subtitles is beneficial for a viewer to know the content of the video presentation more clearly. Subtitles in video are more necessary if the language being played in the video needs to be translated to enable the viewer to understand the content of the video. The plaintext subtitle does not play a role in protecting the subtitle, and the subtitle needs to be encrypted to achieve subtitle protection.

The subtitle file is a file in which a playback period corresponds to a playback sentence, and in the course of playing a video, the sentence (playback sentence) corresponding to the period can be displayed when the video is played for a certain period of time (playback period). Within a preset time period, there may be a sentence with multiple characters or a sentence with only one character, or even no sentence. For a complete video, the total playing time of the video needs to be divided into a plurality of playing time intervals, and then the playing time intervals correspond to the sentences needing to be presented, so as to generate a subtitle file.

Xml, for example, the file name of a subtitle file to be encrypted is sub, and some part of the subtitle file is as follows:

135000000 first sentence >

135000012 second sentence >

That is, under the file name sub, the sentence "first sentence" is output when the playback period is labeled 135000000, and the sentence "second sentence" is output when the playback period is labeled 135000012.

Step 102: obtaining character representation data corresponding to characters in the sentence according to the character comparison table; the character representation data is used for representing characters through data different from the characters, the character comparison table is used for representing the corresponding relation between the characters and the character representation data, the character representation data corresponding to different characters are different, each character representation data in the character comparison table is provided with a sequence mark set according to preset sequencing, and the sequence marks of different character representation data are different.

When the subtitle file is encrypted, the statement in each playing time interval is used as an encrypted subfile to be encrypted for encryption, and the processing mode is to decrypt the statement in the time interval to be played only in the subsequent decryption process instead of decrypting all characters in the encrypted subtitle, so that the risk of stealing the subtitle caused by premature decryption is prevented. Meanwhile, the decryption processing time can be greatly reduced in the subsequent decryption by taking the statement according to the playing time interval as an encryption subunit, so that the problem that the normal playing of the subtitles is influenced due to overlong decryption time is avoided.

In the description, characters in a sentence are represented by character representation data, and optionally, the character representation data has the following two generation manners, which are only exemplary and not specifically limited:

in the first mode, character representation data is generated using a symbol such as a character string, a figure, a letter, a number, or a combination thereof. The characters in the sentence are subjected to symbol conversion, and the characters appearing in the caption are replaced by different symbol marks, so that the aim of being incapable of acquiring the characters in the caption under the condition of not obtaining a character comparison table is achieved, and the encryption effect is achieved.

In the second mode, the character indicating data is image coded data of a character image. When generating character representation data, first, a character image is acquired, image coded data of the character image is generated, and the image coded data is used as character representation data corresponding to characters in the character image.

When the character representation data is image coded data of a character image, the character image has character texture describing the character, and the character texture information can be obtained after the image coded data is restored to the character image. Preferably, the characters in the subtitle are in a dot matrix font, the dot matrix font is formed by dividing one character into 16-by-16 or 24-by-24 points, and then the outline of the character is represented by the virtual reality of each point. Dot matrix fonts, also called bitmap fonts, each glyph is represented by a set of two-dimensional pixel information. Thus, the character representation data is the pixel information array corresponding to the dot matrix font or the binary array converted by the pixel information array. Of course, the character image may be an image containing only one character, and in order to save space, the generated image encoding data of the character image is preferably image compression encoding, and storing the character image by image compression encoding can reduce the storage volume.

The generation method of the character comparison table includes the following three embodiments, which are only exemplary and not specifically limited:

as an embodiment, the generating method of the character comparison table specifically includes: carrying out duplication elimination processing on characters in the subtitle file to be encrypted to obtain duplicated characters; selecting character representation data from the first character representation data set to obtain selected character representation data; the selected character representation data are different from the characters after the duplication removal, and the number of the selected character representation data is not less than the number of the characters after the duplication removal; and corresponding the de-duplicated characters with the selected character representation data, so that each de-duplicated character corresponds to at least one selected character representation data and the character representation data corresponding to different characters are different, and generating a character comparison table.

The characters in the subtitle file to be encrypted are subjected to duplication elimination processing, different characters can be obtained, the different characters need to be distinguished by using different character representation data, and the same character representation data can be used for the same characters. And the character representation data and the characters are corresponding, and at least one character representation data is corresponding to each of the characters after the duplication is removed. Alternatively, a character has only one character representing data corresponding thereto, or a character has two or more character representing data corresponding thereto, as long as it is ensured that the character representing data corresponding to the character does not correspond to other characters than the character. When the character indicating data is image coded data of a character image, since there are a plurality of types of font types of characters, there are a plurality of types of image coded data of character images for the same character, and naturally, when the character image is a hand-drawn image, there are a plurality of types of image coded data of corresponding character images. Any kind of image encoding data can uniquely represent the same character.

The generation mode of the character comparison table is generated for the subtitle file, when the subtitle file is changed, the characters are correspondingly changed, and the character comparison table is changed accordingly. The character comparison table is generated for each subtitle file, so that a cracker needs to find the character comparison table when cracking an encrypted subtitle file, and even if the character comparison table corresponding to one subtitle file is obtained, the comparison table cannot be applied to other subtitle files except the subtitle file, and the cracking workload of the cracker is increased.

Xml, first, all characters used by video in a subtitle file are deduplicated to obtain the following deduplicated characters, wherein the deduplicated characters are represented by a character array charList.

charList [ "first", "sentence", "word", "two" ]

And selecting character representation data from the first character representation data set to obtain the selected character representation data. There are a plurality of character representing data in the first character representing data set, and at least 5 characters selected from the set are corresponding to the de-duplicated characters. When the character representation data are symbol marks such as character strings, graphs, characters, numbers or combinations thereof, the character representation data are randomly selected from a first character representation data set; when the character representation data is the image coding data of the character image, the image coding data of the character image corresponding to the character is selected from the first character representation data set, and one or more image coding data corresponding to the character are stored in the first character representation data set at the moment.

For example, the selected character indicating data '0 x 1111111' corresponds to "the th", the selected character indicating data '0 x 22222' corresponds to "one", the selected symbol indicating data '0 x 333333' corresponds to "sentence", the selected character indicating data '0 x 4444444' corresponds to "speech", and the selected character indicating data '0 x 55555' corresponds to "two".

Thus, character representation data files textureList [ [0x1111111], [0x22222], [0x333333], [0x4444444], [0x55555] ] are obtained. A character corresponds to a character representing a data size of about 0.2Kbyte, and assuming that a movie has 20,000 non-repeating characters, the textrueList is stored in a file size of about 4 MBbyte. The character comparison table is shown in table 1 after the de-duplicated characters are corresponded to the selected character representation data.

TABLE 1 character comparison Table

Character(s)	First, the	A	Sentence	Telephone	II
						Character representation data	0x1111111	0x22222	0x333333	0x4444444	0x55555

From the perspective of the client, UTF8 codes (8-bit, Unicode Transformation Format, for Unicode variable length character coding) of several characters in the caption, namely the "first sentence" and the "second sentence", have not appeared in the memory or the network, and the several characters seen by the user are the result of symbol conversion, that is, the character representation data, that is, the character string, the graph, the character, the number and their combination or the image coding data, are seen.

Compared with the generation of a character comparison table for the whole UTF code table, the generation of a character comparison table for each subtitle file saves the space for storing the character comparison table on one hand, and on the other hand, because the characters after de-duplication in one subtitle file are relatively less, the time for searching the corresponding characters from the table during decompression can be shortened, thereby being beneficial to improving the decompression speed. For example, the total number of the characters obtained after the characters in one video are deduplicated is 1000, and all the characters are far greater than 1000, so that the time for finding the corresponding character from the 1000 characters is far shorter than the time for finding the corresponding character from all the characters.

As another embodiment, the generation method of the character comparison table specifically includes: acquiring a common character set and a second character representation data set; the number of character representation data in the second character representation data set is not less than the number of symbols in the common symbol set; selecting character representation data from the second character representation data set to correspond to characters in the common character set, enabling each character in the common character set to correspond to at least one character representation data in the second character representation data set and enabling the character representation data corresponding to different characters to be different, and generating a character comparison table.

The characters in the common character set are frequently appearing characters, the number of Chinese characters is about one hundred thousand, the number of common characters is small, generally, 1000 common characters can cover 92% of written data, 2000 common characters can cover 98% of written data, and 3000 common characters can cover 99% of written data. Therefore, the generation of the character comparison table corresponding to the characters in the common character set can meet the requirement of subtitles in the video. The number of character representation data in the second character representation data set is not less than that of symbols in the common symbol set, one character representation data can only correspond to one common character, and one common character can be represented by one or more character representation data. For the condition that one common character corresponds to a plurality of character representation data, when the subtitle file is decrypted, the decryption operation can be completed as long as one character is uniquely determined according to the character representation data.

Compared with the method for generating a character comparison table aiming at the whole UTF code table, the method for generating the character comparison table by utilizing the common character set can also save the space for storing the character comparison table. And the number of the commonly used characters is in the range of 1000, 4000, so that the corresponding characters can not be searched from the table in the decompression process, and the decompression speed can be improved.

As another embodiment, the generation method of the character comparison table specifically includes: acquiring a corresponding relation file; the corresponding relation file comprises corresponding relations of a plurality of groups of characters and character representation data, the characters in each group of corresponding relations are different from the character representation data, and the character representation data in different corresponding relations are different; and selecting the corresponding relation between the characters matched with the characters in the subtitle file to be encrypted and the character representation data from the corresponding relation file to generate a character comparison table.

Different from the two generation methods of the character comparison table, the character comparison table generated in this embodiment is generated according to the corresponding relationship between the characters and the character representation data, that is, the character representation data corresponding to each character is fixed and does not change with the difference of the subtitle file, and the character representation data set is not selected for each character in a randomized manner.

Each character representation data in the character comparison table has a sequence mark set according to a preset sequence, and the preset sequence may be generated in a variety of ways, such as one of the following two ways, which are only exemplary and not specifically limited:

in a first mode, the preset ordering is determined according to the arrangement position of the character representation data in the sentence in the character comparison table.

In this way, because the appearance sequence of the characters in each video is different, the character representation data corresponding to the characters is also different. For example, the character "th" appears first in the subtitle file sub.xml, the order of the character representation data '0 x 1111111', corresponding to the "th" word, is marked as 0. While the "th" word may not appear first in other videos, so the corresponding sequence flag is not necessarily 0.

In the second mode, the preset ordering is determined according to the arrangement position of the character representation data in the character comparison table.

In this way, the sequence mark of the character representation data does not change along with the difference of the appearance sequence of the characters, and the sequence mark of the character representation data is determined according to the arrangement position of the character representation data in the character comparison table. For example, the serial number of the character "the first" in the character comparison table is 3, and the sequence number of the corresponding character representing data is 3 no matter when the "the first" appears in the subtitle file.

Step 103: characters in the sentence are replaced by character representation data corresponding to the characters, the characters in the sentence are represented by sequence marks of the character representation data corresponding to the characters, and the arrangement positions of the sequence marks are set according to the arrangement positions of the characters in the sentence, so that a sequence mark set corresponding to the sentence is obtained.

The characters in the sentence are represented by the sequence marks, and the corresponding character representation data can be directly obtained through the sequence marks, and the characters in the sentence can not be directly obtained through the sequence marks, so that a cracker obtains the character representation data which is not a caption file in a video but is different from the characters in the caption file by cracking the sequence marks, and if the cracker wants to further obtain the characters in the caption, the cracker needs to crack to obtain the corresponding relation between the characters and the character representation data, and then the character information in the caption can be extracted. The method can further increase the difficulty and the cracking cost of illegal users or unauthorized users for cracking the characters in the subtitle files.

As an embodiment, when the preset ordering is determined according to the arrangement position of the character representation data in the sentence in the character comparison table, for the subtitle file sub.xml, the sequence of the occurrence of the characters is "first", "sentence", "words", "second", and then, it can be derived from the correspondence relationship between the characters and the character representation data that the sequence of '0 x 1111111' is marked as 0, the sequence of [0x22222] is marked as 1, the sequence of [0x 33333333 ] is marked as 2, the sequence of [0x4444444] is marked as 3, and the sequence of [0x55555] is marked as 4. The characters in the sentence are represented by the sequence marks of the character representation data corresponding to the characters, and the sequence mark set corresponding to the first sentence is [0,1,2,3], and the sequence mark set corresponding to the second sentence is [0,4,2,3 ].

As another embodiment, when the preset sequence is determined according to the arrangement position of the character representation data in the character comparison table, as shown in table 1, since the arrangement position of the "first" character in the character comparison table is the head, the sequence flag of '0 x 1111111' is marked as 0, since the arrangement position of the symbol represented in the character comparison table and the arrangement position of the character representation data in the sentence are the same, the sequence flag set corresponding to the "first sentence" is set as [0,1,2,3], and the sequence flag set corresponding to the "second sentence" is set as [0,4,2,3 ].

Step 104: and splicing the sequence mark sets into the encrypted subtitle files according to the playing time intervals of the sentences corresponding to the sequence mark sets.

The encrypted caption file is a plurality of sequence mark sets with playing time intervals, the encrypted caption file has no characters in the original caption file and no character representation data corresponding to the characters in the original caption file, and the encrypted caption file has a good caption protection effect.

And encrypting the sub.xml of the subtitle file to be encrypted to obtain the new _ sub.xml of the encrypted subtitle file.

Wherein, the encrypted subtitle file new _ sub.xml is as follows:

135000000> [0,1,2,3]// charList [0], charList [1], charList [2], charList [3]

135000012> [0,4,2,3]// charList [0], charList [4], charList [2], charList [3]

Through the step 101-. The server sends the encrypted caption file and the character representation data file to the client at the same time, and the client can restore the encrypted caption file into the caption file to be encrypted only by obtaining the character comparison table after obtaining the two files sent by the server. Because characters in the subtitle files do not appear in the two files received by the client, an attacker is prevented from intercepting from a network or a memory.

Optionally, in order to further increase the subtitle protection effect, after the sequence flag set is obtained, the sequence flag set may be encrypted to obtain an encrypted sequence flag set. And splicing the encrypted sequence mark sets into the encrypted subtitle files according to the playing time intervals of the sentences corresponding to the encrypted sequence mark sets.

The present invention also provides a subtitle file encryption system, as shown in fig. 2, the subtitle file encryption system includes:

a first file obtaining module 201, configured to obtain a subtitle file to be encrypted; the subtitle file comprises a plurality of groups of sentences with playing time interval marks; a sentence includes one or more characters.

The symbol conversion module 202 is configured to obtain character representation data corresponding to characters in a sentence according to the character comparison table; the character representation data is used for representing characters through data different from the characters, the character comparison table is used for representing the corresponding relation between the characters and the character representation data, the character representation data corresponding to different characters are different, each character representation data in the character comparison table is provided with a sequence mark set according to preset sequencing, and the sequence marks of different character representation data are different.

The symbol conversion module 202 specifically includes:

and the character comparison table generating unit is used for generating the character comparison table by adopting at least one of the first mode, the second mode and the third mode.

The first mode specifically includes: carrying out duplication elimination processing on characters in the subtitle file to be encrypted to obtain duplicated characters; selecting character representation data from the first character representation data set to obtain selected character representation data; the selected character representation data are different from the characters after the duplication removal, and the number of the selected character representation data is not less than the number of the characters after the duplication removal; the characters after the duplication removal correspond to the selected character representation data, so that each character after the duplication removal corresponds to at least one selected character representation data and the character representation data corresponding to different characters are different, and a character comparison table is generated;

the second mode specifically comprises: acquiring a common character set and a second character representation data set; the number of character representation data in the second character representation data set is not less than the number of symbols in the common symbol set; selecting character representation data from the second character representation data set to correspond to characters in the common character set, enabling each character in the common character set to correspond to at least one character representation data in the second character representation data set and enabling the character representation data corresponding to different characters to be different, and generating a character comparison table;

the third mode specifically comprises: acquiring a corresponding relation file; the corresponding relation file comprises corresponding relations of a plurality of groups of characters and character representation data, the characters in each group of corresponding relations are different from the character representation data, and the character representation data in different corresponding relations are different; and selecting the corresponding relation between the characters matched with the characters in the subtitle file to be encrypted and the character representation data from the corresponding relation file to generate a character comparison table.

The three ways are similar to the three ways of generating the character comparison table in step 102 shown in fig. 1, and are not described again.

The symbol conversion module 202 further includes:

and the preset sequencing generation unit is used for obtaining the preset sequencing.

As an alternative embodiment, the preset ordering is determined according to the arrangement position of the character representation data in the sentence in the character comparison table.

As another alternative, the predetermined sequence is determined according to the arrangement position of the character representation data in the character comparison table.

The symbol conversion module 202 further includes:

generating character representation data for acquiring a character image; generating image encoding data of a character image; the image encoding data is taken as character representation data corresponding to characters in the character image.

The sequence mark set generating module 203 is configured to replace characters in a sentence with character representation data corresponding to the characters, represent the characters in the sentence with sequence marks included in the character representation data corresponding to the characters, and set arrangement positions of the sequence marks according to arrangement positions of the characters in the sentence to obtain a sequence mark set corresponding to the sentence.

And the encryption module 204 is configured to splice the sequence marker sets into encrypted subtitle files according to the playing time periods of the statements corresponding to the sequence marker sets.

Optionally, the subtitle file encryption system further includes:

and the sequence mark set encryption module is used for encrypting the sequence mark set after the sequence mark set is obtained to obtain an encrypted sequence mark set.

The present invention also provides a subtitle file decryption method, as shown in fig. 3, where the subtitle file decryption method corresponds to the subtitle file encryption method, and the decryption method includes:

step 301: acquiring a subtitle file to be decrypted; the subtitle file to be decrypted comprises a plurality of sequence mark sets spliced according to the playing time interval sequence; the sequence flag set includes a plurality of sequence flags having an arrangement order, the arrangement order of the sequence flags representing an arrangement order of characters in a sentence of the subtitle file.

The subtitle file to be decrypted is provided with a plurality of sequence mark sets, each sequence mark set corresponds to one playing time interval, and when a certain playing time interval is to be played, the sequence mark sets corresponding to the current playing time interval or the time interval to be played are decrypted, so that the effect of decrypting the subtitle file while watching a video is achieved. Compared with the method of decrypting the subtitle file and playing the video content after the subtitle file is decrypted, the method of decrypting while watching can avoid the problem of subtitle decryption caused by early decryption.

Xml, the subtitle file to be decrypted includes two sequential mark sets, one is [0,1,2,3], the corresponding playing time is sub time 135000000, the other is [0,4,2,3], and the corresponding playing time is sub time 135000012.

Since the arrangement order of the sequence numbers represents the arrangement order of characters in the sentence of the subtitle file, when the sequence numbers are 0,1,2, and 3, it means that the character corresponding to 0 is arranged at the first position in the sentence of the subtitle file, the character corresponding to 1 is arranged at the second position in the sentence of the subtitle file, the character corresponding to 2 is arranged at the third position in the sentence of the subtitle file, and the character corresponding to 3 is arranged at the fourth position in the sentence of the subtitle file.

Step 302: and acquiring a sequence mark set corresponding to the playing time interval in the subtitle file to be decrypted to obtain the sequence mark set.

The sequence mark set corresponding to the playing time interval is obtained in the process of playing the video, optionally, the sequence mark set corresponding to the later time intervals of the current playing time interval can also be obtained in the process of playing the video, so that the subsequent sequence mark set is decrypted in advance, and the risk that the normal playing of the subtitles in the video is influenced due to long decryption time can be prevented.

If the subtitle file to be decrypted is new _ sub.xml, when the current playing time period is 135000000, determining that the current sequence tag set is [0,1,2,3], and decrypting the sequence tag set [0,1,2,3 ]; when the current playing time interval is 135000012, the current sequence mark set is determined to be [0,4,2,3], and the decryption operation is performed on the sequence mark set [0,4,2,3 ].

Step 303: representing the sequence mark set by using character representation data with sequence marks set according to preset sequencing, and setting the arrangement position of each character representation data according to the arrangement position of the sequence marks in the sequence mark set to obtain a character representation data set corresponding to the sequence mark set; character representation data is used to represent a character by data different from the character.

Since the character representation data has the sequence marks set according to the preset sequence, the character representation data corresponding to the sequence marks can be converted according to the sequence marks. Optionally, the preset sequence has two generation manners, one is determined according to the arrangement position of the character representation data in the character comparison table in the sentence, and the other is determined according to the arrangement position of the character representation data in the character comparison table. The generation process of the two kinds of preset orderings is similar to the preset ordering generation mode in step 102 shown in fig. 1, and is not described again.

And setting the arrangement position of each character representation data according to the arrangement position of the sequence mark in the current sequence mark set to obtain a character representation data set corresponding to the current sequence mark set. The order of the character representation data in the generated character representation data set can reflect the order of appearance of characters in the sentence of the subtitle file.

If the subtitle file to be decrypted is new _ sub.xml, the current sequence flag set is [0,1,2,3], the character representation data corresponding to the sequence flag 0 is '0 x 1111111', the character representation data corresponding to the sequence flag 1 is '0 x 22222', the character representation data corresponding to the sequence flag 2 is '0 x 333333', the character representation data corresponding to the sequence flag 3 is '0 x 44444', and the character representation data set corresponding to the current sequence flag set [0,1,2,3] can be obtained as [0x1111111,0x22222,0x 333333333333, 0x44444 ] according to the preset arrangement sequence of the character representation data.

Step 304: performing character conversion on character representation data in the character representation data set according to the character comparison table to obtain characters corresponding to the playing time period; the character comparison table is used for representing the corresponding relation between the characters and the character representation data, and the character representation data corresponding to different characters are different.

When character representation data in the character representation data set is subjected to character conversion, the character representation data is converted into characters in the subtitle file by using the character comparison table, and the characters are obtained through decryption. If one character corresponds to a plurality of character representation data, the corresponding character can be obtained by conversion as long as the character representation data can uniquely identify one character. When the character representation data is the image coding data of the character image, the image coding data needs to be decoded and restored to the character image when the character representation data is subjected to character conversion, and then the character displayed at the client is restored according to the character style during coding, for example, for the 'middle' character, the font type during coding is the 'middle' character represented by song, and the font type obtained by decoding is the 'middle' character represented by song. When the character representation data is a symbol mark such as a character string, a figure, a character, a number or a combination thereof, the character corresponding to the character representation data is directly obtained through the character comparison table.

If the subtitle file to be decrypted is new _ sub.xml and the character representation data set is [0x1111111,0x22222,0x333333,0x4444444], when the character representation data '0 x 1111111' is converted, a character comparison table is searched, and as shown in table 1, the corresponding character can be obtained as the 'th'; when the character representation data '0 x 22222' is converted, the corresponding character is found to be 'one'; when the character representation data '0 x 333333' is converted, the corresponding character is found to be a 'sentence'; when the character representation data '0 x 4444444' is converted, the corresponding character is found to be "speech", and the characters corresponding to the current playing time period are the first, sentence and speech, respectively.

The generation manner of the character comparison table is similar to that of the character comparison table in step 102 in fig. 1, and is not described again. There are two ways of generating the character representing data, which are similar to the way of generating the character representing data in step 102 in fig. 1 and are not described again.

Step 305: and sequencing the characters according to the arrangement sequence of the character representation data in the character representation data set to obtain the sentence corresponding to the playing time interval.

And sequencing the characters to obtain the sentences corresponding to the current playing time interval, so that the decryption operation from the sequence mark set corresponding to the current playing time interval to the sentences corresponding to the current playing time interval is completed. In the decryption process, decryption is performed for one playing time interval, and the effect of generating video subtitles while watching videos can be realized by performing decryption operation in which playing time interval is played or which time interval is to be played.

As an optional implementation manner, if the sequence flag set is an encrypted sequence flag set, the encrypted sequence flag set should be decrypted by using a decryption method corresponding to the encryption, and then step 303 is performed.

The present invention also discloses a subtitle file decryption system, as shown in fig. 4, the subtitle file decryption system includes:

a second file obtaining module 401, configured to obtain a subtitle file to be decrypted; the subtitle file to be decrypted comprises a plurality of sequence mark sets spliced according to the playing time interval sequence; the sequence flag set includes a plurality of sequence flags having an arrangement order, the arrangement order of the sequence flags representing an arrangement order of characters in a sentence of the subtitle file.

A set obtaining module 402, configured to obtain, in the subtitle file to be decrypted, a sequence flag set corresponding to the playing time period, to obtain a sequence flag set.

Optionally, if the current sequence marker set is an encrypted sequence marker set, the sequence marker set decryption module is executed, where the sequence marker set decryption module is configured to perform a decryption operation on the current sequence marker set to obtain a decrypted sequence marker set.

A character representation data set generating module 403, configured to represent the sequence marker set by using character representation data with sequence markers set according to a preset sequence, and set an arrangement position of each character representation data according to an arrangement position of the sequence marker in the sequence marker set, so as to obtain a character representation data set corresponding to the sequence marker set; character representation data is used to represent a character by data different from the character.

A character conversion module 404, configured to perform character conversion on character representation data in the character representation data set according to the character comparison table, so as to obtain a character corresponding to the playing time period; the character comparison table is used for representing the corresponding relation between the characters and the character representation data, and the character representation data corresponding to different characters are different.

The character comparison table is generated in three ways, which are similar to the three ways of generating the character comparison table in step 102 shown in fig. 1 and are not described again. There are two ways of generating the character representing data, which are similar to the way of generating the character representing data in step 102 in fig. 1 and are not described again.

The decryption module 405 is configured to sort the characters according to an arrangement order of the character representation data in the character representation data set, so as to obtain a sentence corresponding to the playing time period.

An embodiment of the present invention provides a computer-readable storage medium on which a program is stored, which, when executed by a processor, implements the above-described subtitle file encryption method and/or subtitle file decryption method.

An embodiment of the present invention provides an electronic device, as shown in fig. 5, an electronic device 50 includes at least one processor 501, at least one memory 502 connected to the processor 501, and a bus 503; the processor 501 and the memory 502 complete communication with each other through the bus 503; the processor 501 is configured to call program instructions in the memory 502 to execute the subtitle file encryption method and/or the subtitle file decryption method described above. The electronic device herein may be a server, a PC, a PAD, a mobile phone, etc.

The present application also provides a computer program product adapted to execute a program initialized with the steps comprised by the above-mentioned subtitle file encryption method and/or subtitle file decryption method, when executed on a data processing device.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In a typical configuration, a device includes one or more processors (CPUs), memory, and a bus. The device may also include input/output interfaces, network interfaces, and the like.

The memory may include volatile memory in a computer readable medium, Random Access Memory (RAM) and/or nonvolatile memory such as Read Only Memory (ROM) or flash memory (flash RAM), and the memory includes at least one memory chip. The memory is an example of a computer-readable medium.

Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A subtitle file encryption method is characterized by comprising the following steps:

2. The subtitle file encryption method according to claim 1, wherein the generating manner of the character comparison table includes:

3. The subtitle file encryption method according to claim 1, wherein the generating manner of the character comparison table includes: at least one of the first and second modes:

4. The subtitle file encryption method according to claim 1, wherein the preset ordering is determined according to an arrangement position of the character representation data in the character comparison table in the sentence, or the preset ordering is determined according to an arrangement position of the character representation data in the character comparison table.

5. The subtitle file encryption method according to any one of claims 1 to 4, wherein the method for generating the character representation data specifically includes:

acquiring a character image;

generating image encoding data of the character image;

6. A subtitle file encryption system, comprising:

7. A subtitle file decryption method is characterized by comprising the following steps:

8. A subtitle file decryption system, comprising:

9. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored thereon a program which, when executed by a processor, implements the subtitle file encryption method according to any one of claims 1 to 5 and/or the subtitle file decryption method according to claim 7.

10. An electronic device, comprising:

the processor and the memory complete mutual communication through the bus; the processor is configured to call program instructions in the memory to execute the subtitle file encryption method according to any one of claims 1 to 5 and/or the subtitle file decryption method according to claim 7.