Device for and method of cryptography that allows third party access - 5631961

A device for and method of transmitting an encrypted message and an access field from a sender to a receiver, where a third party may intercept and process the transmission. The sender and receiver agree on a session key. The sender raises an element of a Galois Field to the session key; forms a temporary device unique key; encrypts the session key with the temporary device unique key; forms a temporary family key; encrypts an identifier of the sender and the encrypted session key using the temporary family key; encrypts a plaintext message using the session key; forms the access field by concatenating the element of a Galois Field raised to the session key to the encrypted version of the sender's identifier and the sender's encrypted session key; concatenates the ciphertext to the access field; and transmits the access field and the ciphertext to the receiver. The receiver may recover the plaintext from the sender's transmission. The third party may partially process the transmission to find the identity of the sender. The third party may then request an escrowed key that would allow the third party to recover the plaintext of the sender's message.Device for and method of cryptography that allows third party access563196120/05/199715/09/19951997613Burroughs; John E.Mills; Robert A.Unkenholz; Mark R.Wilson; Mark W.US Patent and Trademark OfficeGoogle Patent keyaccess fieldthird partytemporary family keyencrypted session keyreceiverunique keygalois fieldtemporary device