Least Periods of Generalized Self-Shrinking Sequences
Sun Guo-hua · Microelectronics & Computer · 2007
Stream ciphers use binary sequences with good pseudo randomness as key streams to encrypt messages. By analysing the appearing times of the bit string 101 in generalized self-shrinking sequences b(ak-1) and b(ak+1), it is proved that their least periods reach the maximum, namely 2^(n-1). In the same way, we discuss the least periods of generalized self-shrinking sequences b(ak-1+ak+2),b(ak-2+ak-1),b(ak-2+ak+2),…,etc, it is proved that in most cases their least periods reach the maximum.