AV
Authentication Vector

Either a quintet or a triplet of parameters. The GSM authentication vector uses a triplet of parameters which provides temporary authentication data that enables a VLR (Visitor Location Register) or SGSN (Serving GPRS Support Node) to engage in GSM authentication with a particular user. A triplet consists of three elements: a network challenge termedRAND (Random Number), an expected user response termed SRES (Signed Response) and Kc (Cipher key). The UMTS authentication vector uses a quintet of parameters which provides temporary authentication data that enables an VLR or SGSN to engage in UMTS authentication with a particular user. A quintet consists of five elements: a network challenge (RAND), an expected user response termed XRES (Expected Response), CK (Cipher Key), IK (Integrity Key) and AUTN (Authentication Token).