A Zero Suppression Algorithm for Synchronous Stream Cipher
Hoon Jae Lee, Bongjoo Park, Byung Hwa Chang, SangJae Moon · Applied signal processing · 1998
In synchronous digital communications it is important to recover the receiver clock, but this is difficult when received data contains long consecutive-zero sequences. We suggest a zero suppression (ZS) algorithm, which suppresses consecutive-zero sequences of more than k zeros between successive ones in a ciphertext at the sender of a synchronous stream cipher system, and recovers the original message exactly at the receiver. The probability of k consecutive zeros in ciphertext at the sender is 22k in a synchronous stream cipher without ZS, but 0 with the suggested algorithm. The ZS algorithm does not affect cryptographic security when compared with a synchronous stream cipher without ZS. It is useful for systems which limit consecutive zeros, such as a T1-carrier system (k = 15).