Weaknesses of North American wireless authentication protocol

Security for cellular and PCS systems in the United States will be based on secret key schemes for authentication and encryption. The effectiveness of security for wireless, as in other applications of cryptography, will depend on the ability of the basic cryptographic algorithms to withstand attacks and on sound protocol design. We show the IS-41 authentication protocol to be unsound by pointing to multiple flaws in the protocol which allow a network impersonator to gain service without "breaking the CAVE algorithm". These flaws effectively nullify authentication.