Digital signature protocol
AssigneeCerticom Corp.
InventorScott A. Vanstone
Life of this patent
Estimating the term…
Abstract
A digital signature protocol generates a signature component using a hash of an encrypted message. The component and encrypted message form a signature pair that is forwarded to a recipient. The encryption message is used to retrieve the encryption key at the recipient and authenticate information in the message. The signature pair may be applied to a data carrier as a bar code for use in mail delivery services. By utilizing a hash of the message, a reduced message length is achieved as individual signatures are not required for each component of the message.
Claims13
A digital signature protocol for authenticating digital information transmitted by one correspondent to another over a data communication system, at least said one correspondent having long-term private key and corresponding long-term public key associated therewith, said protocol comprising the steps of said one correspondent generating a short term public key from an integer k, encrypting a message m containing said information with an encryption key derived from said short term public key, to provide a ciphertext e of said message, applying a hash function to said ciphertext to provide a hash e′, generating a signature component, s, incorporating said hash e′, said long-term public key and said integer k, forwarding a signature pair including said ciphertext e and said component s to said other correspondent, hashing said ciphertext e received by said other correspondent with said hash function to obtain a received hash e′*, using said received hash e′*, and said long-term public key to recover said encryption key from said signature component, and retrieving said message m from said ciphertext e by application of said encryption key recovered from said signature component.
Apparatus to generate a digital signature of a message m for transmission over a data communication system, said apparatus comprising an exponentiator to generate a public key r from a short-term private key k, an encryption module to encrypt said message m with a key derived from said public key r, and generate a ciphertext e, a hash function to operate on said ciphertext e and produce a hash e′ of said ciphertext, an arithmetic unit to generate a signature component incorporating said hash e′ and said private key k and a long-term private key, a, and a transmitter to transmit a signature pair comprising said signature component and said ciphertext over said communication system.
Apparatus to verify a digital signature received over data communication system, said apparatus including a receiver to receive a signature pair including ciphertext, e, and a signature component s incorporating a short term private key k, a long-term private key, a, and a hash e′ of ciphertext, e, of a message m, a hash function to operate on said ciphertext e and provide a hash e′*, an arithmetic unit to recover an encryption key correlated to said private key k and an encryption module to apply said encryption key to said ciphertext and recover said message m.
Dependencies are inferred from the claim text.