Identification scheme single or multi-digital signature scheme giving message recovery single or multi-digital signature scheme with appendix key exchange scheme and blind digital signature scheme

摘要

An identification scheme which allows a prover to identify his own identity to a verifier more certainly and prevents already used authentication information from being re-used, a key exchange which uses a common secret key between two users in order not to allow an unauthorized to find it out, a digital signature scheme giving message recovery and digital signature scheme with appendix for producing a digital signature of a message recovery type or appendix type according to the size of a message to be signed, a multi-digital signature scheme for allowing multiple signers to generate digital signatures with respect to the same message and producing them in a message recovery type or appendix type according to the length of the message to be signed, and a blind digital signature scheme for producing a digital signature when a message to be signed should not be opened to the public as well as the signer and therefore a signer does not know the contents thereof.