METHOD AND DEVICE FOR IMPLEMENTING STREAM CIPHER

摘要

The present invention discloses a method and a device for implementing stream cipher. The method includes: implementing a key expansion operation with a pre-set 128-bit initial key and 128-bit initial vector, to obtain 16 31-bit state variables; implementing N-round operations using the state variables, wherein N is a positive integer and in turn each round of operation includes: bit restructuring, nonlinear state filtering operation and variable initialization mode operation; processing the output results after the N-round operations in turn using bit restructuring, nonlinear state filtering operation and discarding the output, as well as the variable work mode operation; implementing the following steps in each clock tick and respectively in turn: bit restructuring, nonlinear state filtering operation, XOR operation, and variable work mode operations, to obtain 32-bit pseudo-random sequence. Application of the method and device described in this invention can be simple and convenient way to obtain the required pseudo-random sequence, and has a high security.