Abstract: Systems and methods for preventing a Man-in-the-Middle attack on a communications network, without combining encryption keys of an inner authentication protocol and a tunneling protocol encapsulating the inner authentication protocol. The performance of a hash function may be split between two network devices on the communications network. For example, in response to a challenge issued by a tunnel server, a client may initiate performance of a hash function using only a first part only of the challenge and generate an intermediate result of the hash function (i.e., a preliminary hash). The client then may transmit the preliminary hash to the tunnel server as part of a response to the challenge. The tunnel server then may complete the hash function using the preliminary hash and the remaining part of the challenge to produce a final hash. The final hash then may be used to authenticate a user.

Abstract: Apparatus for verifying the identity of a party are disclosed, the apparatus including a database memory that stores a password signal encrypted by operation of a one-way commutative function; a number generator that generates an non-repeating number or signal representative thereof; and a processor element that can generate a challenge signal as a function of the number signal and a selected one-way commutative function and that can further generate a key signal as a function of the encrypted password signal and the number. The system includes a communication port for transmitting the generated challenge signal to a party requesting access to the secure system and for receiving a response from the party; and further includes a comparator element for comparing the received response with the generated key signal and for generating a match signal that indicates whether the response signal received from the party is substantially identical to the encrypted password signal stored in the database memory.