Thomas Kunz
Systems and Computer Engineering
40
GSM - Key Generation and Encryption
A8
RAND
Ki
128 bit
128 bit
Kc
64 bit
A8
RAND
Ki
128 bit
128 bit
SRES
RAND
encrypted
data
data
mobile network (BTS)
MS with SIM
AC
BTS
SIM
A5
Kc
64 bit
A5
MS
data
data
cipher
key