Patent ID: 8566593

Claim:
A method of key agreement over an air link of a wireless communication system, the method comprising: at a mobile station, receiving a first message from a base station, including a random NONCE wherein said random NONCE is a number or bit string used only once in a message for a security purpose; computing a permutation of a mobile station identification (MSID*), wherein the permutation is computed using said random NONCE; computing security keys according to: Security keys=DOT16KDF(Parentkey,MSID*|XXX|YYY|,size), wherein, Parentkey is the parent key from which the keys are derived; XXX is more parameters for a specific key such as, for example BSID; YYY is a generic string which is defined per key; and size is the size of the key; sending a second message including a mobile station random NONCE, the base station random NONCE and a first integrity check value (ICV); receiving at said mobile station a third message including a mobile station NONCE, the base station random NONCE and a second ICV if the base station verified the first ICV; verifying the second ICV; and sending a fourth message including mobile station identification in a secure link.