RANDOMNIZATION OF PLAIN TEXT FOR GSM SACCH

摘要

The present document relates to the transmission of data in a digital cellular telecommunications network. In particular, the present document relates to the secure transmission of data over Global System for Mobile Communications (GSM) networks. A method for encoding a SACCH information block in a wireless network is described. The method comprises randomizing a plurality of randomization unit input bits derived from at least some of a plurality of payload bits of the SACCH information block using a pseudo- random bit block, thereby yielding a plurality of randomized bits; and ciphering a plurality of ciphering unit input bits derived from at least some of the plurality of randomized bits, thereby yielding an encoded data burst of a SACCH frame; wherein ciphering is based on a ciphering algorithm using a ciphering key Kc and a frame number COUNT of the SACCH frame; wherein the pseudo-random bit block is determined based on the ciphering key Kc.