Key updating method

Abstract

The invention relates to the fields of cryptography and information security. The invention provides a key updating method based on odd and even keys, which is simple and has high security. The key updating method comprises the following steps of: a. reading an even key as an initialization vector and inputting the initialization vector to a password system; b. intercepting a key stream with predetermined length output by the password system for updating an odd key; c. using the even key for data encryption and decryption; d. when reaching a predetermined key updating time, reading the odd keyas the initialization vector and inputting the initialization vector to the password system; e. intercepting a key stream with predetermined length output by the password system for updating the evenkey; f. using the odd key for data encryption and decryption; and g. when reaching the predetermined key updating time, returning to step a. The key updating method can be applied to a digital interface content protection technology in the field of information security, and also can be applied to other information security systems needing frequent and quick key updating.

Description

technical field [0001] The invention relates to the fields of cryptography and information security. Background technique [0002] There are many kinds of ciphers in practical application at present, but according to the point of view of modern cryptography, cipher systems can be divided into two categories: symmetric cryptography (single-key cryptography) and asymmetric cryptography (double-key cryptography). However, no matter what the encryption mechanism is, theoretically there is a possibility that the encryption algorithm and the length of the key can be deciphered. Therefore, in order to ensure the security of the system, it is impossible to use the same password for a long time for encryption, decryption or signature. There is a key update function. In practical applications, almost all cryptographic systems related to information security need to have key update function, especially those systems with high security requirements. In order to make the generated key ...

AI Technical Summary

Problems solved by technology

[0004] 1. The cryptographic system calls a special random number generation algorithm to generate a set of random numbers as an initialization vector; every time the key is updated, the random number generation algorithm needs to be called to achieve it. In the case of frequent updates, it will bring a lot to the system. overhead

[0005] 2. The cryptographic system uses a fixed sequence to update the initialization vector. Although this method is simple, the security is not high

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