A dual cryptographic keying system. In particular implementations, a method includes responsive to an initial session key negotiation, storing security association information for a tunnel in a security association memory; responsive to a session key renegotiation, storing security association information for the tunnel in a cache; decrypting received packets associated with the tunnel conditionally using the security association information in the cache or the security association information in the security association memory; and upon an expiration condition, overwriting the security association information, for the tunnel, in the security association memory with the security association information, for the tunnel, copied from the cache.