KR101978684B1 - Code-based encryption apparatus and method capable of preventing replay attack - Google Patents

Abstract

A code-based encryption apparatus and method capable of preventing a replay attack are disclosed. A code-based encryption apparatus and method capable of preventing a replay attack according to the present invention is characterized in that in a code-based encryption scheme, a predetermined random number is generated every time encryption is performed and the random number is reflected in the original message, It is possible to minimize the exposure of the original message due to the replay attack of the third party by inducing the pattern to be generated differently.

Description

TECHNICAL FIELD [0001] The present invention relates to a code-based encryption apparatus and method capable of preventing a replay attack,

The present invention relates to a code-based encryption apparatus and method capable of preventing a replay attack that recognizes a generation pattern of an encrypted message and restores an original message from an encrypted message.

Recently, as various types of information are generated and circulated, important information is exposed to a third party due to hacking or transmission of information to a wrong path.

Particularly, in case that important information such as military information or personal information is not applied in the process of transmitting information, and if such important information is accidentally transmitted to a third party, a third party can easily access important information , Can cause great damage.

Recently, in order to prevent exposure of such important information, a technique of encrypting important information by using a predetermined encryption key and transmitting it to the other party has been introduced.

In a general data encryption scheme, when the data transmission side and the data reception side share the same secret key and the data transmission side encrypts and transmits the data with the secret key, a method in which the data reception side decrypts the data with the same secret key is used .

However, such a symmetric key-based cryptosystem has a weak vulnerability in that there is a risk that the corresponding secret key is exposed in the process of transmitting and sharing the secret key.

In order to solve the drawbacks of symmetric key based cryptosystem, data encryption system using asymmetric key, which is a public key and a private key, has been introduced. In the asymmetric key-based data encryption scheme, when the data transmission side encrypts data with the public key and transmits the data to the data reception side, the data reception side decrypts the data with the private key corresponding to the public key, or the data transmission side encrypts the data with the private key When the data is transmitted to the data receiving side, a method in which the data receiving side decrypts the data with the public key is used.

Although a variety of encryption schemes have been introduced in this way, it is a technique to prevent replay attack by analyzing generation pattern of ciphertext if plaintext is always encrypted using the same encryption key. It is possible to consider introducing a technique of encrypting the plaintext data by adding a random number so as to disable the pattern analysis of the ciphertext.

Recently, a code-based encryption method has been introduced to cope with an attack based on a high-performance computer system in an encryption process.

The code-based cryptosystem is such that kxn (k and n), which includes a code value of " 1 " and " 0 " for a linear code having error correction capability for a code of t is a natural number) generation matrix of size G _e and "1" and code of "0" binary nonsingular matrix (binary non-singular matrix) S and "1" and "0" of the kxk size including the code value as a component of the A public key K _pub is generated by using a permutation matrix P having a size of nxn, and a message m to be transmitted to the data receiving device is encrypted with the public key K _pub to generate an encrypted message c, The data receiving apparatus decodes the encrypted message using the generated matrix G _e , the binary regular matrix S, and the permuted matrix P stored in the memory by the data receiving apparatus as a private key, And restores the message m.

In this regard, the data encryption and decryption method in the code-based encryption method will be briefly described as follows.

First, the public key used by a data transmitting apparatus is defined as shown in Equation 1 below is K _pub.

In Equation (1), the generator matrix G _e is a kxn-sized generator matrix having an error correction capability for t-bit codes, S is a randomly determined binary regular matrix having a kxk size, P is a randomly determined nxn Lt; / RTI >

At this time, the data receiving apparatus stores the generation matrix G _e , the binary regular matrix S, and the permutation matrix P, respectively, with a private key corresponding to the public key K _pub in the memory.

Under such circumstances, the data transmission apparatus can generate an encrypted message c by performing an encryption operation according to the following equation (2) for a message m having a size of k bits to be transmitted to the data reception apparatus.

"는 배타적 논리합 연산이다.Where e is a random vector having a length of n bits with a Hamming Weight of t or less,

&Quot; is an exclusive OR operation.

The Hamming weight means the number of bit values " 1 " in the bit string constituting the data.

When the encryption message c is generated, the data transmission device transmits the encryption message c to the data reception device, thereby completing the data encryption transmission.

When the encrypted message c is transmitted from the data transmission apparatus to the data reception apparatus, the data reception apparatus utilizes the generation matrix G _e , the binary regular matrix S and the permutation matrix P stored in the memory And decrypts the encrypted message.

When the encryption message c is received, the data reception apparatus calculates cP ^-1 by multiplying the encrypted message c by the inverse matrix P ^-1 of the permuted matrix P, as shown in Equation (3).

Then, the data receiving apparatus can calculate mS by performing data decoding for error correction using cP ^-1 from the generation matrix G _e .

Since e is a vector having a Hamming weight equal to or less than t and P is a permutation matrix, since eP ^-1 has a Hamming weight of less than or equal to t, cP ^-1 is less than or equal to t bits in codeword mSG _e , The data reception apparatus performs error correction on cP- ¹ using G _e , which is a generation matrix having an error correction capability with respect to t-bit codes stored in the memory So that mS can be decoded.

When the calculation of the mS is completed, the data receiving apparatus multiplies mS by the inverse matrix S ^-1 of the binary regular matrix S stored in the memory, as shown in Equation (4) . ≪ / RTI >

As the importance of data security increases, a code-based encryption scheme is used to protect attacks based on a high-performance computer system. However, in order to block the possibility of a replay attack based on pattern analysis of ciphertexts, The cryptosystem is required to be able to generate different ciphertexts at all times.

A code-based encryption apparatus and method capable of preventing a replay attack according to the present invention is characterized in that in a code-based encryption scheme, a predetermined random number is generated every time encryption is performed and the random number is reflected in the original message, Thereby inducing the pattern to be generated differently so as to minimize the exposure of the original message due to the replay attack of the third party.

A code-based encryption apparatus capable of preventing a replay attack according to an embodiment of the present invention encrypts a padding bit of 1 bit or more with respect to an original message m to be transmitted to a data receiving apparatus so that k (k is a natural number) A padding unit for generating a message M, a random number r having a bit size of q (q is a natural number smaller than k), a first hash function G - the first hash function G, And generating a first hash value G (r) having a k-bit size by performing an exclusive-OR operation on the message M and the first hash value G (r) A first operation unit for generating a first operation value X of a bit size; a second operation unit for multiplying the first operation value X by a second hash function H - the second hash function H reduces an input value of k bits size to an output value of q bits size As a one-way function to input (X) having a q-bit size, and generating a second calculated value Y of q-bit size by performing an XOR operation on the random number r and the second hash value H (X) 2 operation unit, an error vector generating unit for generating an error vector e whose Hamming Weight is t (t is a natural number) and whose size is n (n is a natural number) from the second calculated value Y, An encryption unit for generating an encrypted message c by performing sign-based encryption on the basis of a predetermined public key and an error vector e for the computed value X, and an encrypting message c for transmitting the encrypted message c to the data receiving apparatus And a transmission unit.

Also, a code-based encryption method capable of preventing a replay attack according to an embodiment of the present invention includes padding a padding bit of 1 bit or more with respect to an original message m to be transmitted to a data receiving apparatus, thereby generating a message having k (k is a natural number) Generating a random number r having a bit size of q (q is a natural number smaller than k) as a first hash function G - the first hash function G is a k-bit size input value as an output value of k bits size And generating a first hash value G (r) having a k-bit size by performing an exclusive-OR operation on the message M and the first hash value G (r) The first hash function H and the second hash function H are bidirectional functions that reduce the input value of the k-bit size to the output value of the q-bit size. - as an input to generating a second hash value H (X) having a q-bit size, performing a XOR operation on the random number r and the second hash value H (X) to generate a second calculated value Y of q-bit size, Generating an error vector e having a hamming weight t (t is a natural number) and a size n (n is a natural number) from the second calculated value Y, Generating an encrypted message c by performing sign-based encryption based on the error vector e, and transmitting the encrypted message c to the data receiving device.

A code-based encryption apparatus and method capable of preventing a replay attack according to the present invention is characterized in that in a code-based encryption scheme, a predetermined random number is generated every time encryption is performed and the random number is reflected in the original message, It is possible to minimize the exposure of the original message due to the replay attack of the third party by inducing the pattern to be generated differently.

1 is a block diagram of a code-based encryption apparatus capable of preventing a replay attack according to an embodiment of the present invention.
2 is a flowchart illustrating a code-based encryption method capable of preventing a replay attack according to an embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. It is to be understood that the description is not intended to limit the invention to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals in the drawings are used for similar elements and, unless otherwise defined, all terms used in the specification, including technical and scientific terms, are to be construed in a manner that is familiar to those skilled in the art. It has the same meaning as commonly understood by those who have it.

1 is a block diagram of a code-based encryption apparatus capable of preventing a replay attack according to an embodiment of the present invention.

Referring to FIG. 1, a code-based encryption apparatus 110 capable of preventing a replay attack according to the present invention includes a padding unit 111, a first computing unit 112, a second computing unit 113, an error vector generating unit 114, An encryption unit 115, and an encrypted message transmission unit 116. [

The padding unit 111 generates a message M having a bit size of k (where k is a natural number) by padding a padding bit of 1 bit or more with respect to the original message m to be transmitted to the data receiving apparatus 120. [

At this time, the padding bit may be a bit value of " 0 ". For example, when the original message m is " 1010 ", and k is " 8 ", the padding unit 111 paddes a bit value " 0 "Quot; 10100000 ".

The first calculation unit 112 generates a first hash value G (r) having a k-bit size by inputting a random number r having a bit size of q (q is a natural number smaller than k) as an input to the first hash function G , And performs a XOR operation on the message M and the first hash value G (r) as shown in Equation (5) below to generate a first calculated value X of k bits.

Here, the first hash function G is a one-way function for expanding a q-bit input value to an k-bit output value.

"는 배타적 논리합 연산을 의미한다.In Equation (5)

"Means an exclusive OR operation.

The second calculation unit 113 generates a second hash value H (X) having a q-bit size by applying the first calculated value X to the second hash function H as an input, The second hash value H (X) is XORed with the random number r and the second hash value H

Here, the second hash function H is a one-way function that reduces the k-bit input value to the q-bit output value.

The error vector generating unit 114 generates an error vector e whose Hamming Weight is t (t is a natural number) and whose size is n (n is a natural number) from the second calculated value Y. [

In this case, according to an embodiment of the present invention, the error vector generating unit 114 generates a error vector for a mapping function designed to map an input value of a q-bit size to an output value of n-bit size having a hamming weight of t The error value e may be generated by applying the second calculated value Y as an input.

As described above, the mapping function is a function that converts an input value of q bits in size to an output value of n bits in size having a hamming weight of t when the input value is input, Likewise, input according to the "Mapping bit strings to constant weight codewords" scheme proposed in the prior art "Raphael Overbeck, Nicolas Sendrier," Code-Based Cryptography ", Post-Quantum Cryptography, pp.95-145. And converting the value to an output value.

출력 값:

, 이때, 출력 값은 길이가

이고, 해밍 무게가

인 워드(word)라고 할 때,

사전식 순서(lexicographic order) 내의

의 인덱스(Index)로 정수(integer)이고,

일 동안, 아래의 과정을 반복 수행함으로써, 출력 값을 생성함
『

만약,

이면,

이고,
그렇지 않으면,

임
그러고 나서,

』Input Value:

Output Value:

, The output value is the length

, Hamming weight

When a word is referred to,

Within a lexicographic order

Is an integer (integer)

During the day, the following process is repeated to generate the output value
"

if,

If so,

ego,
Otherwise,

being
and then,

"

Assuming that a mapping function for converting an input value of 4 bits to an output value of 10 bits having a Hamming weight of "6" is designed according to the logic shown in Table 1, an input value of "0101" is mapped to "1101001101" And an input value of " 1101 " may be mapped to " 1011000111 ".

The mapping function according to Table 1 is characterized in that when an input value is mapped to an output value and an inverse operation of the mapping function according to Table 1 is performed, the input value can be inversely transformed from the output value.

Based on this mapping function, the error vector generator 114 can generate the error vector e of n-bit size having the Hamming weight of t by applying the second calculated value Y as an input.

According to another embodiment of the present invention, the error vector generator 114 may be configured to generate the error vector e by applying the second calculated value Y to the mapping function as shown in Table 1 above, but q For each of 2 ^q different input values having a bit size, a mapping table in which different output values having n bits size are mapped and which has a hamming weight of t is constructed in advance, and the mapping table is referred to And generate an output value mapped to an input value equal to the second calculated value Y from the table as the error vector e.

That is, if the process of calculating the error vector e using the mapping function as shown in Table 1 is performed, it may take a long time due to the operation. Therefore, the manager may calculate 2 ^q different input values The output values according to the mapping function as shown in Table 1 are calculated in advance and configured as a predetermined mapping table so that the error vector generating unit 114 generates the error vector corresponding to the second calculated value Y The error vector e may be directly detected.

When the generation of the error vector e is completed, the encryption unit 115 performs code-based encryption on the first computation value X based on a predetermined public key and the error vector e, thereby generating an encrypted message c .

In this case, according to an embodiment of the present invention, the code-based encryption apparatus 110 capable of preventing a replay attack may further include a public key storage unit 117.

1 " and " 0 " s, having error correcting capability for a code of t bits, and a public key storage unit 117, a generation matrix of kxn size including the code value of ingredient G _e and "1" and "0" of the code value, the public key the became the permutation matrix P of nxn size product selection, including the component K _pub (K _pub = SG _e P) is stored.

In association with this, the public key storage unit 117 stores the selected public key K _pub according to Equation (7) below.

At this time, the encryption unit 115 multiplies the first computation value X by the public key K _pub to generate a result c ', and performs an exclusive-OR operation on the result c' and the error vector e, An encrypted message c can be generated.

In this regard, the encryption unit 115 may generate the encrypted message c according to the following equation (8).

When the generation of the encrypted message c is completed, the encrypted message transmitting unit 116 transmits the encrypted message c to the data receiving apparatus 120. [

When the encrypted message c according to the operation of Equation (8) is transmitted to the data receiving apparatus 120, the data receiving apparatus 120 can decrypt the encrypted message c to recover the original message m. Hereinafter, The process of restoring the original message m from the encrypted message c will now be described in detail.

First, the data receiving apparatus 120 stores the binary regular matrix S, the generation matrix G _e, and the permutation matrix P as a private key corresponding to the public key K _pub on the memory, The function G, the second hash function H, and the mapping function.

If the encryption message c is received by the data reception apparatus 120, the data reception apparatus 120 extracts the binary regular matrix S, the generation matrix G _e, and the permutation By performing error correction based on the matrix P, the first computation value X can be recovered.

In response to the encryption message c, the data receiving apparatus 120 calculates the inverse matrix P ^-1 of the permutation matrix P stored in the memory with respect to the encrypted message c according to the following equation (9) Can be multiplied to calculate cP ^-1 .

Then, the data receiving apparatus 120 performs error correction on the cP ^-1 based on the generation matrix G _e , and calculates the XS multiplied by the first computation value X and the binary normality matrix S .

Here, since the error vector e is a vector having t Hamming weights and P is a permutation matrix, eP ^-1 has t Hamming weights, so that cP ^-1 is the sum of t bits in the codeword XSG _e The data receiving apparatus 120 performs error correction on cP- ¹ using G _e , which is a generation matrix having an error correction capability for the t-bit code stored in the memory So that XS can be decoded.

When the operation of XS is completed, the data receiving apparatus 120 multiplies the XS by the inverse matrix S ^-1 of the binary regular matrix S according to the operation of Equation (10) to restore the first operation value X .

When the restoration of the first calculation value X is completed, the data reception device 120 extracts the restored first calculation value X, the binary regularity matrix S, the generation matrix G _e, and the permutation matrix C from the encryption message c P, and performs an inverse operation on the extracted error vector e with respect to the mapping function, thereby restoring the second calculated value Y, and then, by using the first hash function G and the second hash function e, 2 decoding the original message m by restoring the message M from the restored first calculation value X and the restored second calculation value Y based on the second hash function H and removing the padding bits from the restored message M, can do.

When the restoration of the first computation value X is completed, the data reception apparatus 120 transmits the restored first computation value X and the binary normality X to the encryption message c according to the following equation (11) The error vector e can be extracted by performing exclusive-OR of the result of multiplication by the matrix S, the generation matrix G _e, and the permutation matrix P, respectively.

Then, the data receiving apparatus 120 can restore the second calculated value Y by performing an inverse operation on the extracted error vector e with respect to the mapping function.

If the encrypted message c is generated on the basis of the error vector e generated in the predetermined mapping table in the code-based encryption apparatus 110 capable of preventing a replay attack, the data receiving apparatus 120 is provided with a memory- The data receiving apparatus 120 may store the mapping table instead of storing the mapping function in the mapping table and if the error vector e is extracted according to the operation of Equation 11, The second calculated value Y can be recovered by finding an input value mapped to the error vector e.

When the restoration of the second calculation value Y is completed, the data reception device 120 applies the restored first calculation value X as an input to the second hash function H stored in the memory, 2, the random number r is recovered by performing an exclusive OR operation on the restored second calculation value Y and the second hash value H (X) according to the following equation (12) after calculating the hash value H (X) .

Then, the data receiving apparatus 120 calculates the first hash value G (r) by applying the restored random number r as an input to the first hash function G stored in the memory, 13, the message M can be restored by exclusive-ORing the restored first calculation value X and the first hash value G (r).

When the restoration of the message M is completed, the data reception apparatus 120 can decode the original message m by removing the padding bits from the restored message M.

As a result, the code-based encryption apparatus 110 capable of preventing the replay attack according to the present invention generates a predetermined random number every time encryption is performed in the code-based encryption scheme, and reflects the random number in the original message every time It is possible to minimize the exposure of the original message due to the replay attack of the third party by inducing the pattern of the encrypted message to be generated differently.

2 is a flowchart illustrating a code-based encryption method capable of preventing a replay attack according to an embodiment of the present invention.

In step S210, a padding bit of 1 bit or more is padded to the original message m to be transmitted to the data receiving apparatus to generate a message M having k (k is a natural number) bit size.

In step S220, a random number r having a bit size of q (q is a natural number smaller than k) is input to the first hash function G to generate a first hash value G (r) having a k-bit size, The message M and the first hash value G (r) are XORed to generate a first calculated value X of k bits.

Here, the first hash function G is a one-way function for expanding a q-bit input value to an k-bit output value.

In step S230, the first calculation value X is input to the second hash function H to generate a second hash value H (X) having a q-bit size, and the random number r and the second hash value H X) to generate a second calculated value Y having a q-bit size.

Here, the second hash function H is a one-way function that reduces the k-bit input value to the q-bit output value.

In step S240, an error vector e having a hamming weight t (t is a natural number) and a size n (n is a natural number) is generated from the second calculated value Y. [

According to an embodiment of the present invention, in step S240, a mapping function designed to map an input value having a q-bit size to an output value having an n-bit size having a hamming weight of t is compared with the second calculation value Y May be applied as an input to generate the error vector e.

According to another embodiment of the present invention, in step S240, for each of 2 ^q different input values having a q-bit size, different output values having an n-bit size having a Hamming weight of t are mapped An output value mapped to the same input value as the second calculated value Y can be generated from the mapping table as the error vector e.

In step S250, code-based encryption is performed based on the selected public key and the error vector e for the first computation value X, thereby generating an encrypted message c.

According to an embodiment of the present invention, a code-based encryption method capable of preventing a replay attack includes a kxk-sized binary regularity matrix S including code values of "1" and "0" and includes a kxn-sized generator matrix G _e and a code value of " 1 " and a code value of " 0 " having a code correction value for a code of t bits and including code values of & and maintaining the public key storage unit in which the selected public key K _pub (K _pub = SG _e P) multiplied by the permutation matrix P of size nxn is stored.

At this time, in step S250, the first calculation value X is multiplied by the public key K _pub to generate a result c ', and an exclusive OR operation is performed on the result c' and the error vector e, Message c can be generated.

In step S260, the encryption message c is transmitted to the data receiving apparatus.

According to an embodiment of the present invention, the data receiving apparatus stores the binary regular matrix S, the generation matrix G _e, and the permutation matrix P as a private key corresponding to the public key K _pub , respectively, in a memory And may store the first hash function G, the second hash function H, and the mapping function.

At this time, when the encryption message c is received, the data reception device performs error correction based on the binary regular matrix S, the generation matrix G _e, and the permuted matrix P stored in the memory from the encryption message c The first computation value X and the recovered first computation value X, the binary normals matrix S, the generation matrix G _e, and the permutation matrix P from the encrypted message c And then performs an inverse operation on the extracted error vector e with respect to the mapping function to restore the second calculated value Y, and then the first hash function G and the second hash function e H, the message M is recovered from the restored first calculation value X and the restored second calculation value Y to remove the padding bits from the recovered message M, And can decode the original message m.

In this regard, according to an embodiment of the present invention, when the encrypted message c is received, the data receiving apparatus multiplies the encrypted message c by the inverse matrix P ^-1 of the permuted matrix P stored in the memory, ^-1 , performs an error correction on the cP- ¹ based on the generation matrix G _e , calculates an XS multiplied by the first computation value X and the binary normality matrix S, The first calculation value X can be recovered by multiplying the inverse matrix S ^-1 of the binary regular matrix S. [

Then, the data receiving apparatus performs an exclusive OR operation on the recovered first computation value X and the result of the binary normals matrix S, the generation matrix G _e, and the permuted matrix P, The second calculation value Y can be recovered by extracting the error vector e and performing an inverse operation on the extracted error vector e with respect to the mapping function.

Thereafter, the data receiving apparatus applies the restored first calculation value X as an input to the second hash function H to calculate the second hash value H (X), and outputs the restored second calculation value Y And the second hash value H (X), the random number r can be restored.

The data receiving apparatus calculates the first hash value G (r) by applying the restored random number r as an input to the first hash function G when the restoration of the random number r is completed, The original message m can be decrypted by performing an exclusive OR operation on the first calculated value X and the first hashed value G (r) to recover the message M and then remove the padding bits from the recovered message M.

2, a code-based encryption method capable of preventing a replay attack according to an embodiment of the present invention has been described. Here, the code-based encryption method capable of preventing a replay attack according to an embodiment of the present invention can correspond to the configuration of the operation of the code-based encryption apparatus 110 capable of preventing the replay attack described with reference to FIG. 1, A detailed description thereof will be omitted.

A code-based encryption method capable of preventing a replay attack according to an embodiment of the present invention can be implemented by a computer program stored in a storage medium for execution through a combination with a computer.

In addition, the code-based encryption method capable of preventing a replay attack according to an embodiment of the present invention can be implemented in the form of a program command which can be executed through various computer means and recorded in a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like.

As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and specific embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

110: Code-based encryption device capable of preventing playback attack
111: padding unit 112: first calculation unit
113: second operation unit 114: error vector generation unit
115: encryption unit 116: encrypted message transmission unit
117: public key storage unit 120: data receiving apparatus

Claims (14)

A binary regular matrix S of kxk size including the code values of " 1 " and " 0 " as elements, code values of "1" and "0" a predetermined public key K _pub (K _pub = SG _e P) obtained by multiplying a generation matrix G _e of kxn size and a permutation matrix P of nxn size containing code values of "1" and "0" A stored public key storage unit;
A padding unit for padding a padding bit of 1 or more bits with respect to an original message m to be transmitted to the data receiving apparatus to generate a message M having k (k is a natural number) bit size;
a random number r having a bit size q (q is a natural number smaller than k) is a first hash function G - the first hash function G is a one-way function for expanding an input value of a q-bit size to an output value of a k- And generates a first hash value G (r) having a k-bit size by performing an exclusive-OR operation on the message M and the first hash value G (r) A first calculation unit for generating a first calculation result;
The first hash function H and the second hash function H are input to the input of the k-bit input value as an output value of the q-bit size, A second arithmetic unit for generating a second hash value H (X), performing a XOR operation on the random number r and the second hash value H (X) to generate a second arithmetic value Y of q bits;
An error vector generator for generating an error vector e having a Hamming Weight t (t is a natural number) and a size n (n is a natural number) from the second calculated value Y;
An encryption unit for generating an encrypted message c by performing code-based encryption on the first computation value X based on the public key K _pub and the error vector e; And
An encryption message transmission unit for transmitting the encryption message c to the data reception device,
Lt; / RTI >
The encryption unit
Generating an encrypted message c by performing an exclusive-OR operation on the result c 'and the error vector e by multiplying the first computed value X by the public key K _pub to generate a result c' Code-based encryption device capable of preventing unauthorized access. delete The method according to claim 1,
The error vector generation unit
a mapping function designed to map an input value of a q-bit size to an output value of an n-bit size having a hamming weight of t, A code-based encryption device capable of preventing attacks. The method according to claim 1,
The error vector generation unit
for each of 2 ^q different input values having a q-bit size, referring to a mapping table in which different output values having an n-bit size are mapped with a Hamming weight of t, And generates an output value mapped to an input value equal to the value Y as the error vector e. The method of claim 3,
The data receiving apparatus
Storing the binary regular matrix S, the generator matrix G _e, and the permutation matrix P as a private key corresponding to the public key K _pub on the memory, and storing the first hash function G and the second hash function H And the mapping function,
When the encryption message c is received, performs error correction based on the binary regular matrix S, the generation matrix G _e, and the permutation matrix P stored in the memory from the encryption message c, Restores the value X,
Extracting the error vector e from the recovered first computation value X, the binary normals matrix S, the generation matrix G _e, and the permutation matrix P from the encryption message c, Mapping function, and restoring the second computation value Y by using the restored first computation value X and the restored second computation value X based on the first hash function G and the second hash function H, And decrypting the original message m by recovering the message M from the computed value Y and removing the padding bits from the recovered message M. 6. The method of claim 5,
The data receiving apparatus
If the encrypted message c is received, the encryption of a message and c calculated by multiplying an inverse matrix P ^{-1 -1} a cP of a permutation matrix P, which is stored on the memory, the cP based on the generator matrix G _e ^{- 1} to calculate an XS multiplied by the first computation value X and the binary normals matrix S and then multiply the XS by the inverse matrix S ^-1 of the binary normals matrix S to calculate the first computation value X Lt; / RTI >
The error vector e is extracted by performing an exclusive OR operation on the recovered first computation value X, the binary normals matrix S, the generation matrix G _e, and the permutation matrix P, Performing an inverse operation on the extracted error vector e with respect to the mapping function to restore the second calculated value Y,
(X) by applying the restored first calculation value X to the second hash function H, and outputs the restored second calculation value Y and the second hash value H (X) X), thereby restoring the random number r,
The first hash value G is computed by applying the restored random number r to the first hash function G as an input, and the first hash value G (r) is computed using the restored first computation value X and the first hash value G And decrypting the original message m by removing the padding bits from the restored message M after restoring the message M by exclusive-ORing the original message m. A binary regular matrix S of kxk size including the code values of " 1 " and " 0 " as elements, code values of "1" and "0" a predetermined public key K _pub (K _pub = SG _e P) obtained by multiplying a generation matrix G _e of kxn size and a permutation matrix P of nxn size containing code values of "1" and "0" Maintaining a stored public key storage;
Padding a padding bit of 1 bit or more with respect to the original message m to be transmitted to the data receiving apparatus to generate a message M having k (k is a natural number) bit size;
a random number r having a bit size q (q is a natural number smaller than k) is a first hash function G - the first hash function G is a one-way function for expanding an input value of a q-bit size to an output value of a k- And generates a first hash value G (r) having a k-bit size by performing an exclusive-OR operation on the message M and the first hash value G (r) ≪ / RTI >
The first hash function H and the second hash function H are input to the input of the k-bit input value as an output value of the q-bit size, Generating a second hash value H (X), performing a XOR operation on the random number r and the second hash value H (X) to generate a second calculated value Y of q bit size;
Generating an error vector e having a Hamming Weight t (t is a natural number) and a size n (n is a natural number) from the second calculated value Y;
Generating an encrypted message c by performing code-based encryption on the first computed value X based on the public key K _pub and the error vector e; And
Transmitting the encrypted message c to the data receiving apparatus
Lt; / RTI >
The step of generating the encrypted message c
Generating an encrypted message c by performing an exclusive-OR operation on the result c 'and the error vector e by multiplying the first computed value X by the public key K _pub to generate a result c' Code - based encryption method that can prevent. delete 8. The method of claim 7,
The step of generating the error vector e
a mapping function designed to map an input value of a q-bit size to an output value of an n-bit size having a hamming weight of t, A code - based encryption method capable of preventing attacks. 8. The method of claim 7,
The step of generating the error vector e
for each of 2 ^q different input values having a q-bit size, referring to a mapping table in which different output values having an n-bit size are mapped with a Hamming weight of t, And generating an output value mapped to an input value equal to the value Y as the error vector e. 10. The method of claim 9,
The data receiving apparatus
Storing the binary regular matrix S, the generator matrix G _e, and the permutation matrix P as a private key corresponding to the public key K _pub on the memory, and storing the first hash function G and the second hash function H And the mapping function,
When the encryption message c is received, performs error correction based on the binary regular matrix S, the generation matrix G _e, and the permutation matrix P stored in the memory from the encryption message c, Restores the value X,
Extracting the error vector e from the recovered first computation value X, the binary normals matrix S, the generation matrix G _e, and the permutation matrix P from the encryption message c, Mapping function, and restoring the second computation value Y by using the restored first computation value X and the restored second computation value X based on the first hash function G and the second hash function H, And decoding the original message m by recovering the message M from the computed value Y and removing the padding bits from the recovered message M. 12. The method of claim 11,
The data receiving apparatus
If the encrypted message c is received, the encryption of a message and c calculated by multiplying an inverse matrix P ^{-1 -1} a cP of a permutation matrix P, which is stored on the memory, the cP based on the generator matrix G _e ^{- 1} to calculate an XS multiplied by the first computation value X and the binary normals matrix S and then multiply the XS by the inverse matrix S ^-1 of the binary normals matrix S to calculate the first computation value X Lt; / RTI >
The error vector e is extracted by performing an exclusive OR operation on the recovered first computation value X, the binary normals matrix S, the generation matrix G _e, and the permutation matrix P, Performing an inverse operation on the extracted error vector e with respect to the mapping function to restore the second calculated value Y,
(X) by applying the restored first calculation value X to the second hash function H, and outputs the restored second calculation value Y and the second hash value H (X) X), thereby restoring the random number r,
The first hash value G is computed by applying the restored random number r to the first hash function G as an input, and the first hash value G (r) is computed using the restored first computation value X and the first hash value G Wherein the original message m is decrypted by removing the padding bits from the restored message M after restoring the message M by exclusive-ORing. A computer-readable recording medium recording a program for performing the method of any one of claims 7, 9, 10, 11, and 12. A computer program stored in a storage medium for executing the method of any one of claims 7, 9, 10, 11, or 12 through a combination with a computer.

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