Encryption Method of Inner Round Permutation Stream Cipher with Variable Key

Abstract

The invention discloses an inner wheel displacement flow password encryption method with a variable key. In the method, different mathematical operators are adopted, so that the confusion among key bits is realized rapidly; a bit mixing scrambling technique for combining ''longitudinal'' diffusion with ''transverse'' compression is adopted in the computation of key flow bytes; the key flow bytes are obtained by adopting a multi-wheel ''iteration'' method, so that attack resistance of an algorithm is ensured; a fixed constant is introduced, so that an inner wheel function structure is damaged, and slipping attacks are avoided; resistance to time-space compromise attack is ensured through the lengths of a seed key and an initial vector; operators of the algorithm appear alternately and are distributed uniformly, so that general side channel attack, particularly power analysis attacks can be resisted; an iteration internal state in which 15 wheels is adopted has sufficient robustness, so that the traditional differential attacks can be resisted sufficiently; the length of the seed key can be selected according to the safety strength; the algorithm is concise, and has high safety; and each key flow block is generated separately, so that the method is particularly suitable for parallel computation, is easy and rapid for realizing software and hardware, and is implemented flexibly on various platforms.

Description

technical field [0001] The invention relates to the field of information security, in particular to an encryption method of an inner round permutation stream cipher with a variable key. Background technique [0002] In the process of data transmission, some sensitive data needs to be encrypted to prevent the attacker from eavesdropping, so that the attacker can only eavesdrop on the ciphertext but cannot obtain any useful information, and only the legitimate receiver who has the key can decrypt and restore the real news. In data encryption algorithms, there are two types of encryption algorithms. One is the block encryption algorithm, and the other is the stream cipher encryption algorithm (also known as the sequence cipher). The encrypted data of the block encryption algorithm is of fixed length (divided into groups), while the encryption length of the stream cipher encryption algorithm is a value with a large variable range. The block cipher uses a certain size as the b...

AI Technical Summary

Problems solved by technology

First, the message sender and receiver share a seed key k through a secure channel. For each bit of plaintext xi, the sender uses a stream cipher encryption algorithm to generate a corresponding one-bit key stream zi, and then uses zi and The ciphertext yi is obtained by XORing the plaintext with xi, that is, After receiving yi, the receiver of the message uses the same method and the same key to generate the same key stream bit zi, and the plaintext xi can be recovered after XORing zi and yi, namely However, the internal operation of the traditional stream cipher encryption algorithm is not easy to realize, the internal scrambling effect is not good, and it is vulnerable to attacks. Therefore, the traditional stream cipher encryption algorithm needs to be further improved.

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