PREVENTION OF UNAUTHORIZED FORWARDING AND AUTHENTICATION OF SIGNATURES

A forwarding signature comprises a modified digital signature, modified using a predetermined parameter between a sender and an intended recipient. An intended recipient of the forwarding signature can verify that the forwarding signature corresponds to the message, but, can neither derive the original digital signature nor generate a new forwarding signature for a different parameter. Generation and verification of the forwarding signature is accomplished with access to the public key of a public/private cryptographic key pair, the original signed message, and the predetermined parameter. Access to the private key is not needed.