Undeniable certificates for digital signature verification

A method for generating an undeniable signature from a signer to a recipient on a message, wherein said signer sends said undeniable certificate thereby eliminating the need for a trusted third party, comprising the steps:

• generating a first key pair an undeniable signature scheme comprising a first private signing key and a corresponding first public vertification key, said first private signing key for verifying undeniable signatures generated under the first private signing key;
• generating a second key pair for a digital signature scheme comprising a second private signing key and a corresponding public verification key, said second public verification key for verifying a signature on a message generated with the second private signing key;
• signing said second public vertification key by the signer using the first undeniable private signing key to generate an undeniable certificate of the second public verification key;
• sending to the recipient said undeniable certificate of the second public verification key;
• interacting in a confirmation protocol between said signer and said recipient, said signer needing no prior knowledge of said recipient, using the first undeniable public verification key to verify to the recipient that said undeniable certificate was signed using the first undeniable private signing key, said recipient accepting or rejecting said undeniable certificate;
• the signer signing a message to create a signature using the second signing key associated with the second verification key certified by said undeniable certificate;
• and
• the recipient verifying said signature with the second vertification key certified by said undeniable certificate.

A computer readable medium containing code for operating a computer system to generate an undeniable certificates from a signer to a recipient thereby eliminating the need for a trusted third party, wherein said signer sends said undeniable certificate, said code implementing the steps of:

• generating a first key pair for an undeniable signature scheme comprising a first private signing key and a corresponding first public verification key, said first public verification key for verifying undeniable signatures generated under the first private signing key;
• generating a second key pair for a digital signature scheme comprising a second private signing key and a corresponding public verification key, said second public vertification key for verifying a signature on a message generated with the second private signing key;
• allowing a signer to sign said second public verification key by the signer using the first undeniable private key to generate an undeniable certificate of the second public verification key;
• sending to the recipient said undeniable certificate of the second public verification key;
• and
• implementing a confirmation protocol between said signer and said recipient, said signer needing no prior knowledge of said recipient, using the first undeniable public verification key to verify to the recipient that said undeniable certificate was signal using the first undeniable private signing key, said recipient accepting or rejecting said undeniable certificate.