AES-based 192-bit key extension system and method

Abstract

The invention discloses a 192 bit key expansion system and method based on an AES (Advanced Encryption Standard), which are used for mainly solving the problems of low efficiency and high power consumption of the traditional 192 bit AES encryption algorithm in a key expansion process. The method comprises the steps of: storing an initial key in a first turn of key expansion, taking the front four lines as turn keys of the turn of key expansion, carrying out word circulation, byte replacement and bitwise XOR operation; using results as the turn keys and storing the results in a local register and an external memory unit, reading by an encryption process; and finally, repeating the operation for the turn keys obtained in the former turn in each turn until all 12 turn keys are obtained, and ending the key expansion. The 192 bit secret key expansion system and method can be compatible with the instantaneity of the key expansion and the reusability of the turn keys, realize high-efficiency and low-consumption key expansion, and is suitable for a 192 bit key expansion process of the AES encryption algorithm.

Description

technical field [0001] The invention belongs to the technical field of safety, relates to data encryption, in particular to a key expansion method in the Advanced Encryption Standard AES, which can be used for network communication. Background technique [0002] In November 2001, the National Institute of Standards and Technology NIST of the US Department of Commerce published the Advanced Encryption Standard AES, which is an algorithm for unclassified encryption. Since its release, the AES algorithm has been widely used in high-end products such as encryption protocols, communication terminals, and servers. [0003] The AES algorithm adopts a subset of the Rijnddel symmetric key algorithm, and supports groups with a length of 128 bits and keys with lengths of 128, 192, and 256 bits. The algorithm obtains the round key by performing key expansion on the initial key, and uses the round key to encrypt and decrypt 128-bit data blocks. [0004] In the AES algorithm, depending ...

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Problems solved by technology

[0005] There are currently two widely used key expansion methods: one is the real-time key expansion method used in "A Rijndael Cryptoprocessor Using Shared On-the-fly Key Scheduler", that is, the key expansion unit performs key expansion at the same time Provide a round key for the encryption process; the disadvantage of this method is that the round key cannot be reused, so for occasions where the amount of data is large and the round key needs to be used continuously, the power consumption caused by the continuous execution of the key expansion operation is relatively large; The other is the pre-key expansion method used in "An Optimized FPGA Implementation Method of AES Algorithm", that is, the key expansion is performed first to generate all the round keys and stored in the memory, and then encrypted; in this method In the process of encryption, since the encryption process can only be performed after the key expansion is completed, the time required for encryption is increased and the efficiency of the entire encryption process is reduced.

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