A system for authentication of a crypto-system user by the use of both symmetric and asymmetric crypto-keys is provided. A first network station, representing the user, transmits a first request for authentication to a second network station. The second station generates a shared symmetric crypto-key, encrypts it and forwards it to both the first station and a third network station. The third station encrypts the received shared symmetric crypto-key and forwards it to the first network station. The first network station combines the two instances of the received and encrypted shared symmetric crypto-key, decrypts the combined symmetric crypto-key to recover shared symmetric crypto-key, encrypts a second authentication request with the recovered shared symmetric crypto-key, and transmits the encrypted authentication request to authenticate the first station. Each transmission of the shared symmetric crypto-key is encrypted with different portion of different ones of multiple asymmetric crypto-keys, each associated with a network station.