Cryptographic key generation using parameters based on a set of generated keys, an incrementing sequence number and an anonymity key

摘要

Disclosed is a method of generating a cryptographic key (120) for the protection of communications between two entities. The method is carried out by the first entity (100) as part of a distributed security operation initiated by the second entity. The method makes use of at least two parameters (106, 108), the first of which (106) comprises or is derived from a set of cryptographic keys (110, 112) that have been computed by the first entity (100) by running the security operation. The second parameter (108) comprises or is derived from a token (116) which has a different value each time the security operation is initiated. The token (116) comprises the output of an exclusive OR operation on a sequence number and an anonymity key. The method is performed by applying a key derivation function to generate a cryptographic key (120) based on the at least two parameters (106, 108). A device (100) for performing the method is also disclosed.