KR20160099865A - Device For Performing Block Cipher Algorithm HIGHT - Google Patents

Abstract

An apparatus for encoding and decoding block cipher HIGHT which calculates 64-bit data by block cipher HIGHT, comprising: a round calculation unit which divides input 64-bit data into upper 32 bits and lower 32 bits and performs calculations during 34 rounds; a key scheduler unit which generates a plurality of sub-keys and a plurality of whitening keys by using a master key, and provides the sub-keys and whitening keys to the round calculation unit; and a control unit which controls operations of the round calculation unit and the key scheduler unit in accordance with control of a clock signal and a mode signal.

Description

[0001] The present invention relates to an encryption / decryption apparatus for a block cipher HIGHT,

The present invention relates to an encryption / decryption apparatus for a block cipher HIGHT, and more particularly, to an encryption / decryption apparatus for a block cipher HIGHT which implements a block cipher algorithm HIGHT (HIGh security and light weigHT) with lightened hardware.

Encryption is a process of encoding a message so that its meaning is unclear, and decryption is the process of converting an encrypted message into its original form. The original form of the message is called plaintext, and the encrypted form is called a ciphertext. Cryptography has been used mainly for confidential communication such as military use in the past, but now it is widely used for mail transmission, user authentication, electronic commerce, etc. as core technology for safety, reliability and privacy protection of the Internet based social and economic activity .

A symmetric cryptosystem is a system in which the key held by the sender used for encryption and the key of the recipient to be used for decryption are the same. Symmetric block cipher algorithms have been presented in various ways such as DES (Data Encryption Standard), T-DES, IDEA (International Data Encryption Algorithm), SKIPJACK, MISTY and AES (Advanced Encryption Standard) In Korea, we have also introduced the symmetric block cipher algorithms SEED and ARIA.

HIG (security and light weigHT) encryption algorithm, which is a 64-bit block encryption technology for mobile, which is finally approved as an ISO / IEC international standard in 2010, is being implemented in hardware.

However, since conventional hardware that implements the HIGHT security and light weigHT (HIGHT) encryption algorithm uses too many gates and memories at the logic level, it is required to develop a technique for reducing the weight.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned technical problems, and it is an object of the present invention to provide an encryption / decryption method of a block cipher HIGHT capable of reducing the size of hardware logic by dividing input 64-bit data into upper 32- Device.

According to an embodiment of the present invention, a round operator for dividing input 64-bit data into upper 32-bit and lower 32-bit data and calculating the data for 34 rounds when computing 64-bit data with a block cipher HIGHT; A key scheduler for generating a plurality of sub keys and a plurality of whitening keys using the master key, and providing the plurality of sub keys and the plurality of whitening keys to the round operator; And a controller for controlling operations of the round calculator and the key scheduler according to the control of the clock signal and the mode signal.

The key scheduler may provide the respective whitening keys in the first round and the final round, and provide the respective subkeys in the remaining rounds.

The encryption / decryption apparatus of the block cipher HIGHT according to the embodiment of the present invention shares the operation logic to be used repeatedly so that the input 64-bit data can be divided into upper 32 bits and lower 32 bits, Respectively. Therefore, the use of hardware logic, gate, latch, and the like is reduced, so that not only the hardware can be lightened but also the power consumption can be reduced due to the lightweight hardware.

1 is a block diagram showing the concept of a block cipher HIGHT;
2 is an i < th > round function of the block cipher HIGHT.
3 is a 32 < th > round function of the block cipher HIGHT.
FIG. 4 shows the overall encryption structure of the block cipher HIGHT.
5 is a block diagram of an apparatus for encrypting / decrypting a block cipher HIGHT according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention.

1 is a block diagram showing the concept of a block cipher HIGHT, Fig. 2 is an i-th round function of a block cipher HIGHT, Fig. 3 is a 32nd round function of a block cipher HIGHT, 5 is a block diagram of an encryption / decryption apparatus for a block cipher HIGHT according to an embodiment of the present invention.

HIGHT (HIGh security and light weigHT) is a symmetric key block cipher algorithm that encrypts 64-bit plaintext (ciphertext) block with 128-bit master key to generate 64-bit ciphertext (plaintext). Based on the modified Feistel structure, encryption (decryption) is performed through a total of 34 rounds of operations, and a subkey generated from the 128-bit master key is used for the round conversion. Round conversion and sub-key generation are realized by simple operations such as mod-2 ⁸ addition, cyclic shift, and mod-2 addition in bytes, and it is possible to implement small hardware and low power suitable for mobile and object internet environments. .

The overall structure of the HIGHT algorithm is constituted by a total of 34 round conversions including an initial conversion, 32 round conversions, and final conversions as shown in FIG. 1, and the initial conversion and the final conversion are performed only by adding whitening keys without cyclic movement. The encryption process and the decryption process are performed in the reverse order. The modulo addition process of the encryption process is implemented by modulo subtraction in the decryption process, and the direction of the circulation movement is also reversed.

The 64-bit block cipher HIGHT can be used to provide functions such as confidentiality of data and the like by using a 128-bit cipher key to encrypt and decrypt the message in 64-bit block units. This standard describes the process of round key generation of 64-bit block cipher HIGHT and the round function which constitutes the whole structure and the inside of the algorithm.

The overall structure of HIGHT is composed of a generalized Feistel transformation structure. It is composed of 64 bits of plain text, 8 8-bit whitening keys generated from 128-bit keys, and 128 8-bit subkeys, Print the cipher text. Figure 1 shows the overall structure of the HIGHT algorithm.

Referring to FIG. 1, a round key of HIGHT includes sub keys generated using a whitening key and an LFSR.

The whitening key is generated using the master key in the following manner.

LFSR

The connection polynomial of

to be. This polynomial

Is a primitive polynomial in

The

.

The initial internal state value of

. then

about

Is generated as follows.

Is 127

to be.

The algorithm for generating the subkey is configured as follows.

LFSR

Are the values of the internal state of < / RTI >

In order to perform the encryption algorithm of HIGHT, the round key generation process includes eight whitening keys in byte units

And 128 subkeys

.

HIGHT's decryption algorithm uses the same whitening key and subkey bytes as the encryption algorithm, but in a different order. In the decryption algorithm

In this initial conversion,

Is used for the final conversion. The subkey bytes used in the decryption algorithm

And is defined as follows.

The initial conversion of HIGHT encryption consists of four whitening key bytes

Using plain text

To the input of the first round function .

The round function of HIGHT has two auxiliary functions as follows.

2 is an i < th > round function of the block cipher HIGHT. Referring to Figure 2, the round function

from

To 32 times.

bracket

The third round function

The

of

As shown in FIG.

3 is a 32 < th > round function of the block cipher HIGHT. Referring to FIG. 3,

Does not mix bytes. Therefore,

The output value

Is calculated as follows and is shown in FIG.

The final conversion of HIGHT is

Output of

To four whitening keys

.

Encryption consists of an initial conversion, a round function 32 times, and a final conversion of the subkey and plaintext block generated through the key schedule.

HIGHT's decryption algorithm consists of a round key generation process, an initial transformation (inverse transformation of the encryption final transformation), a round function 32 times, and a final transformation (inverse transformation of the initial encryption transformation). The intermediate value in the decryption algorithm is

.

The initial transformation of the decryption algorithm is the inverse of the final transformation of the encryption algorithm. This function has four whitening keys

The ciphertext

The input value of the first round function of the decryption algorithm

As follows.

Decryption algorithm

The third round function

.

The third round function

The

To

As shown below.

As in the encryption algorithm, the last round function

Does not mix bytes. Therefore, the output is calculated as follows.

The final transformation of the decryption algorithm corresponds to the inverse of the initial transformation in the encryption algorithm. This function uses four whitening keys

Using the last round function

The output value

A plain text

.

5 is a block diagram of an apparatus for encrypting / decrypting a block cipher HIGHT according to an embodiment of the present invention. The encryption / decryption apparatus for the block cipher HIGHT according to the present embodiment includes only a simple structure for clearly explaining the technical idea to be proposed.

Referring to FIG. 5, the apparatus for encrypting / decrypting a block cipher HIGHT includes a round operator 100, a key scheduler 200, and a controller 300.

The detailed configuration and main operation of the encryption / decryption apparatus for the block cipher HIGHT constituted as above will be described below.

The rounding unit 100 divides the input 64-bit data DIN into upper 32-bit and lower 32-bit data for the 34 rounds of operation, when computing the 64-bit data DIN with the block cipher HIGHT. That is, the round calculator 100 calculates the data DIN with the function set 34 times and outputs the calculated output data DOUT. At this time, the output data DOUT is a cipher text when the input data DOUT is a plain text, and the output data DOUT is a plain text if the input data DOUT is a cipher text. That is, the rounding unit 100 internally calculates the lower 32 bits of the 64-bit data DOUT for 34 rounds, then calculates the upper 32 bits for the 34 rounds using the same logic, The 32-bit operation result is combined and output as output data DOUT.

The key scheduler unit 200 generates a plurality of sub keys SUB KEY and a plurality of whitening keys using a master key and transmits a plurality of sub keys SUB KEY to the round unit 100. [ And a plurality of whitening keys (WHITENING). The key scheduler unit 200 provides respective whitening keys in the first round and the final round, and provides the respective subkeys in the remaining rounds.

The controller 300 controls operations of the round calculator 100 and the key scheduler 200 according to the control of the clock signal CLK and the mode signal MODE. The mode signal MODE is a signal for selecting either the encryption or decryption operation in the round calculator 100.

The encrypting / decrypting apparatus for the block cipher HIGHT according to the embodiment of the present invention reduces the size of the hardware by sharing the repeatedly used arithmetic logic so that the inputted 64-bit data can be divided into the upper 32 bits and the lower 32 bits, . Therefore, the use of hardware logic, gate, latch, and the like is reduced, so that not only the hardware can be lightened but also the power consumption can be reduced due to the lightweight hardware.

Thus, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: round operator
200: key scheduler section
300:

Claims (2)

A round operator for dividing the 64-bit data input into upper 32 bits and lower 32 bits and calculating the data for 34 rounds;
A key scheduler for generating a plurality of sub keys and a plurality of whitening keys using the master key, and providing the plurality of sub keys and the plurality of whitening keys to the round operator; And
A controller for controlling operations of the round calculator and the key scheduler according to control of a clock signal and a mode signal;
And encrypting / decrypting the block cipher HIGHT.
The method according to claim 1,
Wherein the key scheduler comprises:
Wherein each whitening key is provided in a first round and a final round, and each subkey is provided in the remaining rounds.

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