Patent ID: 7720221

Claim:
A method of transferring information stored in a machine readable document pertaining to a correspondent to a machine for examination, said information including a sensitive portion to be kept confidential during transmission, comprising the steps of: assembling at said correspondent a message having a primary portion M 1 containing said sensitive portion of said information retrieved from said machine readable document, and a secondary portion M 2 containing less sensitive portion of said information and including a long term public key of said correspondent, generating an encryption key e from a session private key and said long term public key of the correspondent, encrypting said primary portion with said encryption key e to obtain a ciphertext C, combining said ciphertext C and said secondary portion M 2 and generating a signature component s of said correspondent from said combination, transferring said signature component s, said ciphertext C and said secondary portion of M 2 to the machine, said machine generating a value from said signature component s, said ciphertext C and said secondary portion M 2 , generating an ephemeral private key, and utilizing said value and said ephemeral private key to generate a public session key from said value and said ephemeral private key, forwarding said public session key to said correspondent and obtaining from said correspondent a further public key to permit recovery of said encryption key e, and said machine recovering said primary portion M 1 from said ciphertext C using said encryption key e.