128 bit secret key expansion method based on AES (advanced encryption standard)

Abstract

The invention discloses a 128 bit secret key expansion system and a method based on an AES (Advanced Encryption Standard), which mainly solve the problems of low efficiency and high power consumption in a 128 bit secret key expansion process of an existing AES encryption algorithm. A realization process comprises the following steps of: storing an initial secret key at a first round of secret key expansion; using the stored initial secret key as a round secret key of the round; carrying out word circulation, byte substitution and bitwise XOR operation on the round secret key; storing the round secret key in a local register and an external storage unit simultaneously so as to be read by an encryption process; repeating the operation on the round secret key obtained through the former round; and finishing secret key expansion until 10 round secret keys are obtained. According to the 128 bit secret key expansion system and method based on the AES, the instantaneity of secret key expansion and the reusability of the round secret key can be ensured, the high efficiency and the low power consumption of secret key expansion are realized; and the system and the method can be applied to the 128 bit secret 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] The Advanced Encryption Standard AES is an algorithm for unclassified encryption published by NIST, the National Institute of Standards and Technology of the US Department of Commerce in November 2001. Since its publication, the AES algorithm has been widely used in high-end products such as encryption protocols, communication terminals, and servers. [0003] The AES 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. The algorithm adopts a subset of the Rijndael symmetric key algorithm, and supports blocks with a length of 128 bits and keys with lengths of 128, 192, and 256 bits. [0004] The algorithm determines the rou...

AI Technical Summary

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 provides round-robin for the encryption process in real time. key; the disadvantage of this method is that the round key cannot be reused, so for the occasions where the amount of data is large and the round key needs to be used continuously, the power consumption brought by the continuous operation of the key expansion program is relatively large;

[0006] The other is the pre-key expansion method used in "An Optimized FPGA Implementation Method of AES Algorithm", which first performs key expansion to generate all round keys, stores them in memory, and then encrypts them; in this method In this method, since the encryption process can only be performed after the key expansion is completed, which increases the time required for encryption, it cannot be applied to occasions that require real-time encryption

Images