Section: 10.5.3.1 Authentication parameter RAND
Content: The purpose of the Authentication Parameter RAND information element is to provide the mobile station with a non-predictable number to be used to calculate the authentication response signature SRES and the ciphering key Kc (for a GSM authentication challenge), or the response RES and both the ciphering key CK and integrity key IK (for a UMTS authentication challenge). The Authentication Parameter RAND information element is coded as shown in figure 10.5.75/3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ]  and table 10.5.89/3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ] . The Authentication Parameter RAND is a type 3 information element with 17 octets length. Figure 10.5.75/3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ]  Authentication Parameter RAND information element Table 10.5.89/3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ] : Authentication Parameter RAND information element