What is CK (Ciphering key)?

The Ciphering Key is a variable utilized in the GSM and GPRS cipher procedure. It is applied to ciphering algorithms from the A5 range to create a cipher stream. It is determined in the authentication procedure and utilized for the encryption of the Radio Bearer in UMTS. This is modulo 2 added to customer information to shield it from eavesdropping. This is a 128bit number. It is determined in the authentication procedure and utilized for the encryption of the Radio Bearer in UMTS.