KR101566416B1 - Method and device of data encription with increased security - Google Patents

Abstract

The present invention relates to a device and a method to encode and decode digital content or the like to prevent from being illegally used. The present invention provides the device and the method to encode and decode which increases a security by additionally converting a binary code of encryption data, and maintains an advantage of the encryption speed by applying a lightweight encryption encoding method. The device comprises: a key setting module to set a unique key; a hash module to generate an encryption key of a block unit; a content data module to store the content data; a measurement module to generate temporary encryption data; and an encryption module to generate encryption data.

Description

TECHNICAL FIELD [0001] The present invention relates to an apparatus and a method for encrypting and decrypting data,

The present invention relates to an apparatus and method for encrypting and decrypting digital contents and the like so that a user can not illegally use the apparatus, and more particularly, to an apparatus and method for encrypting and decrypting improved security.

As the development of Internet information and communication technology and the emergence of mobile devices such as smart phones have increased the use of open networks, the digital contents distribution market has been activated. In this background, CDN (Content Delicer Network) technology is being studied to quickly deliver moving images to users. The CDN service refers to a service that uses caching technology to distribute content to a cache server while using existing network structure facilities without modification and to provide content from a near cache server according to a user's request. Recently, researches about efficient arrangement of multiple cache servers, efficient storage of contents, and reduction of traffic between networks have been actively carried out in relation to CDN technology.

On the other hand, the Internet has an advantage that anyone can easily access desired information. However, since the data may be illegally circulated by an unauthorized user, the security of the data spread on the digital network becomes increasingly important. However, the CDN technology has a problem in that it is vulnerable to security such as copyright protection and piracy because digital contents are widely distributed and stored.

Conventionally, in order to secure content data, content data is transmitted using a block encryption algorithm. However, this method has a problem in that it requires a large amount of time for encryption / decryption in transmission of a large amount of content and is vulnerable to a speed aspect.

In the past, scrambling cryptography has been used as a lightweight encryption method that improves the speed aspect. The scrambling encryption scheme transforms or encrypts original content data by a specific key, and allows only a user having a specific key to restore the image normally. According to the scrambling encryption scheme, even if an unauthorized user decrypts a received image, the user scrambles the original image, but sees the distorted image.

However, in the case of the scrambling encryption scheme, when the encrypted image and a part of the original frame are exposed, the image after the exposed frame can be decrypted, resulting in a problem of poor security. Therefore, in the case of the lightweight encryption method, an encryption algorithm with improved security has become necessary.

Therefore, it is an object of the present invention to provide an apparatus and method for encrypting and decrypting data with high encryption speed and improved security, so that a user can receive contents more securely.

According to an aspect of the present invention, there is provided a content providing apparatus including: a key setting module for setting a unique key for encrypting content data; A hash module for hashing the unique key to generate an encryption key in units of blocks; A content data module for dividing and storing content data in block units; An operation module for generating temporary encryption data by calculating the encryption key and the content data, and an encryption module for converting the binary code of the temporary encryption data to generate encrypted data.

According to another aspect of the present invention, there is provided an information processing method comprising the steps of: (a) setting a unique key for encrypting content data; (b) a hash step of hashing the unique key to generate an encryption key in units of blocks; (c) dividing and storing the content data in blocks; (d) generating temporary encryption data by computing an encryption key and content data; and (e) encrypting the binary code of the temporary encrypted data to generate encrypted data.

According to another aspect of the present invention, there is provided a method of encrypting encrypted data, comprising: a key setting module for receiving a unique key for decrypting encrypted data; a hash module for generating an encryption key in units of blocks by hashing the unique key; A temporary decryption module, and a decryption module for recovering contents data by calculating temporary encryption data and an encryption key.

According to the present invention, the binary code of the encrypted data is additionally converted to improve the security, and the advantage of the encryption speed is maintained by applying the lightweight encryption technique.

1 shows an encryption apparatus according to an embodiment of the present invention.
2 shows an encryption process according to an embodiment of the present invention.
3 shows a decoding apparatus according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to or limited by the exemplary embodiments. Like reference numerals in the drawings denote members performing substantially the same function.

1 shows an encryption apparatus 10 according to an embodiment of the present invention. 1, the encryption apparatus 10 includes a key setting module 101 for setting a unique key for encrypting content data, a hash module 103 for generating an encryption key in block units by hashing a unique key, A calculation module 107 for calculating an encryption key and content data to generate temporary encryption data, and an encryption module 107 for converting the binary code of the temporary encryption data and generating encrypted data, Module 109, as shown in FIG.

When encrypting a plaintext to be protected, the plaintext is converted to a ciphertext by computing a specific argument with a plaintext. Unless the specific argument is disclosed, the third party can not decipher the cipher text because it can not know the operation process. This particular argument is called a unique key. Accordingly, the unique key functions as an ID that allows only a specific user to encrypt and decrypt content data.

The key setting module 101 sets this unique key. The setting method may be specified by the user, or may be set to a specific data value corresponding to the type or size of the content data.

The hash module 103 may generate a cryptographic key for performing an operation with the content data by hashing the unique key designated from the key setting module 101. [ The hash can be understood to represent the data in a shortened manner. More specifically, the hash function performs a function of mapping data of an arbitrary length into data of a fixed length by cutting and replacing arbitrary data. If the two hash values mapped from the hash function are different, the hash value is different from the original data for the hash value, but the inverse is not established. The hash value can be used for electronic signature, electronic fingerprint, and the like.

In this embodiment, the hash module 103 can hash the unique key using a SHA (Secure Hash Algorithm) hash function. In this case, if the value obtained by hashing the initial unique key is a first encryption key, the second mapped hash value is obtained by hashing the first encryption key. This can be shown in Table 1.

The first encryption key SHA-512 (unique key) The second encryption key SHA-512 (first encryption key) The (n + 1) -th encryption key SHA-512 (nth encryption key)

The SHA-512 function means mapping a unique key having an arbitrary data length to 512 bits. Although the present embodiment has been described on the assumption that the mapping is performed with a length of 512 bits, the data length to be mapped is determined by the content data length of the content data module 105 to be described later and can be changed.

Accordingly, the hash module 103 generates an encryption key corresponding to the content data size based on the unique key set for the specific user to be able to be encrypted and decrypted. The hash function has a characteristic that it can not find the n-th cipher key with the (n + 1) -th cipher key, which is advantageous in security.

The content data module 105 may divide and store the content data to be protected in blocks. The content data may include a digital image, a document, or the like that can be distributed in a network. In this embodiment, when the content data is 512 bits, the content data block may be composed of 6 bits of binary code.

In this case, the 512-bit content data may be composed of 86 content data blocks, and the hash module 103 may generate the encryption key by the number of the content data blocks. Thus, the hash module 103 can hash the 86 encryption keys made up of 6-bit binary codes so as to match each content data block.

The operation module 107 can generate the temporary encryption data by calculating the binary code of the encryption key and the binary code of the content data block using an XOR (exclusive or) operation. According to the above embodiment, the 6-bit encryption key and the 6-bit content data block are operated 86 times. As a result, the operation module 107 generates temporary encrypted data consisting of 86 temporary encrypted data blocks of 6 bits.

The encryption module 109 can generate the encrypted data by calculating the adjacent two bits from the binary code of the temporary encryption data by the beta logical operation (XOR). More specifically, the encryption module 109 performs a bitwise logical operation (XOR) on the two adjacent bits in the descending order of the binary codes of the temporary encryption data. However, the first bit of the converted encrypted data may be the same as the first bit of the temporary encrypted data.

In a case where the binary code of the temporary encryption data is '0011', if two bits adjacent to each other in the descending order are subjected to a bitwise logical operation (XOR), '0' and '0', '0' and '1' (XOR) '1' respectively. Third, and fourth bits of the encrypted data, respectively, and the first bit may be the same as the first bit '0' of the temporary encrypted data. This logic is summarized as follows.

Temporary encryption data (0011) Encrypted data '0' '0' '0' XOR '0' '0' '0' XOR '1' 'One' '1' XOR '1' '0'

Therefore, the binary code '0011' of the temporary encryption data is converted into the encrypted data of '0010'. In the present embodiment, when the temporary encryption data block is 86, the above logical conversion can be performed 86 times for each block or once for all the temporary encrypted data bits consisting of 86 temporary encrypted data blocks.

As described above, unlike the operation module 107 that converts data using an encryption key, which is a specific argument, the encryption module 109 has a function of converting the code itself of the data (temporary encryption data) to be converted by a certain rule do.

The encryption module 109 secondarily converts the temporary encryption data converted by the encryption key, thereby increasing the security by increasing the arguments and calculation logic that the unauthorized general user needs to know in decoding. Moreover, the configuration of the logic circuit of the XOR can be implemented simply and inexpensively, and the advantage of the encryption speed is maintained in that it does not require any additional argument.

2 shows the encryption process. According to another aspect of the present invention, there is provided an encryption method including: (a) a key setting step of setting a unique key for encrypting content data; (b) a hash step of generating an encryption key in block units by hashing a unique key; (D) generating temporary encryption data by computing an encryption key and content data, and (e) encrypting the binary data of the temporary encryption data to generate encrypted data. Step < / RTI >

Although each step of the encryption method is not shown in the drawing, step (a) is a key setting module 101, step (b) is a hash module 103, step (c) ) May be understood as a function performed by the operation module 107, and (e) by the encryption module 109, respectively.

The process of encrypting with reference to FIG. 2 will be described as an embodiment.

In order to encrypt and decrypt content data, the user can set a unique key called 'konkuk'. A unique key called 'konkuk' can be firstly hashed and become a first encryption key made up of a binary code of a certain length. Thereafter, the first encryption unit is hashed and the second hashed key becomes the second encryption key. With this principle, an encryption key is generated by the number of content data blocks.

Then, the operation module 107 converts the first content data block with the first encryption key. In the present embodiment, when the first encryption key '58ECF9' and the first content data block '333896' are XORed, the first content data block is converted into temporary encrypted data '6BD46F'.

Thereafter, the encryption module 109 converts the temporarily encrypted data '6BD46F' into the above-mentioned logical operation to generate encrypted data '5EBE58'. In the case of passing through such an encryption process, even if an unauthorized general user finds the n-th encryption key, the image after the n-th frame can not be restored, thereby improving the security of the content data.

3 shows a decoding apparatus 30 according to an embodiment of the present invention. 3, the decryption apparatus 30 includes a key setting module 301 for receiving a unique key for decrypting encrypted data, a hash module 303 for generating an encryption key in units of blocks by hashing the unique key, A temporary decryption module 307 for generating temporary encryption data by converting the binary code of the data, and a decryption module 309 for recovering the content data by calculating the temporary encryption data and the encryption key.

The decryption apparatus 30 is an apparatus for recovering content data encrypted by the encrypting apparatus 10 of FIG. 1, and can be understood as an apparatus for performing an inverse process of the encrypting apparatus 10. The key setting module 301 and the hash module 303 perform the same functions as described above. However, the unique key set in the key setting module 301 is the same as the specific key input from the user to be used for encryption.

The encryption data module 305 receives the encrypted data, and the temporary decryption module 307 converts the encrypted data into temporary encrypted data. The temporary decryption module 307 sets the first bit value in the binary code of the encrypted data as the first bit value of the temporary encrypted data and XORs the first bit value of the temporary encrypted data and the second bit value of the encrypted data, Th bit value. With this logic, the second bit value of the temporary encryption data and the third bit value of the encrypted data are XORed to be the third bit value of the temporary encrypted data.

When the binary code of the encrypted data is' 0010 ', the first bit value of the temporary encrypted data is' 0', which is the first bit value of the encrypted data, and the second bit value of the temporary encrypted data is' '0' and the second bit value of the encrypted data are '0', which is the XOR result. Table 3 shows these processes. As a result, it can be confirmed that the operation opposite to the encryption module 109 is performed.

Encryption data (0010) Temporary encryption data '0' '0' '0' XOR '0' '0' '0' XOR '1' 'One' '1' XOR '0' 'One'

The decryption module 309 performs an operation of XORing the temporary encryption data and the encryption key. In this case, the value of the contents data block is finally restored. With this process, the user can decode the content data.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. will be. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by all changes or modifications derived from the scope of the appended claims and equivalents of the following claims.

10: Encryption device 101: Key setting module
103: Hash module 105: Content data module
107: Operation module 109: Encryption module
30: Decryption unit 301: Key setting module
303: Hash module 305: Encrypted data module
307: temporary decryption module 309: decryption module

Claims (9)

In an encryption device with improved security,
A key setting module for setting a unique key for encrypting content data;
A hash module for hashing the unique key to generate an encryption key in units of blocks;
A content data module for dividing and storing the content data on a block-by-block basis;
An operation module for operating the encryption key and the content data to generate temporary encryption data; And
And an encryption module for converting the binary code of the temporary encryption data to generate encrypted data,
The hash module includes:
Generates a first encryption key by hashing the unique key, generates a second encryption key by hashing the first encryption key,
The encryption module includes:
The temporary encryption data converted by the encryption key is secondarily converted and then decrypted when the temporary encryption data is converted by using a binary logical operation (XOR) of the binary code of the temporary encryption data to generate the encrypted data And increases the argument and operation logic.
delete The method according to claim 1,
The hash module may include: And generates the encryption key by the number of blocks.
The method according to claim 1,
Wherein the operation module generates the temporary encryption data by calculating a binary code of the encryption key and a binary code of the content data block using a beta logical operation (XOR).
delete 1. An encryption method with improved security,
(a) a key setting step of setting a unique key for encrypting content data;
(b) a hashing step of hashing the unique key to generate an encryption key in units of blocks;
(c) dividing the content data into blocks and storing the blocks;
(d) computing the encryption key and the content data to generate temporary encryption data; And
(e) an encryption step of converting the binary code of the temporary encryption data to generate encrypted data,
The step (b)
Generates a first encryption key by hashing the unique key, generates a second encryption key by hashing the first encryption key,
The step (e)
The temporary encryption data converted by the encryption key is secondarily converted and then decrypted when the temporary encryption data is converted by using a binary logical operation (XOR) of the binary code of the temporary encryption data to generate the encrypted data And the arithmetic logic is increased.
The method according to claim 6,
Wherein the generating of the temporary encryption data by the binary logical operation (XOR) of the binary code of the encryption key and the binary code of the content data block is performed by the step (d).
delete delete

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