Research On Distinguishing Attack Of A New Stream Cipher Sturcture

Many stream ciphers are based on linear feedback shift registers and non-linear Boolean function,because linear feedback shift register has many advantages, such as, hardware simple, fast and the sequence produced has good statistical properties.This structure has been used for many years for its advantages. Recently, algebraic attack and fast correlation attack have been found to be very effective to this structure. In order to find a good stream cipher algorithm as world standard for data encryption, Europe has launched ECRYPT project after NESSIE, and the ECRYPT Stream Cipher Project has collected many good stream cipher algorithms. At present, research and analysis of the candidate algorithms to ECRYPT is a hot spot of stream cipher. This thesis is mainly based on the study of Grain algorithm which is a very competitive candidate algorithm to ECRYPT.A new stream cipher structure has been extracted from Grain algorithm. This structure is based on one linear feedback shift register, one non-linear source and one non-linear Boolean function.A distinguishing attack based on the theory of hypothesis testing is presented. The result shows that, this stream cipher structure has potential security weakness when the design of the filter Boolean function is improper.