A New Guess-and-Determine Method for Cryptanalysis of the GSM Encryption

Table 1

Percentage saving in finding unknown bit.

REG2[10]	REG2[20]	REG3[10]	REG3[20]	Number of cases	Valid cases	Saving cases (%)
Known	Known	Known	Known	0	0	0
Known	Known	Unknown	Unknown	4	2	50
Unknown	Unknown	Known	Known	4	2	50
Unknown	Unknown	Unknown	Unknown	16	8	50
Unknown	Unknown	Known	Unknown	8	4	50
Known	Known	Known	Unknown	2	2	0