Undeniable signature
Encyclopedia
Undeniable signatures are a form of digital signature
invented by David Chaum
and Hans van Antwerpen in 1989. They have two distinctive features,
The first means that a signatory can allow only others who are authorized to access the document to verify their signature. If the document were to be leaked to a third party, the third party would be unable to verify that the signature is genuine. This is a designated verifier signature
.
However, because of this property it means that the signatory may deny a signature which was valid. To prevent this, there is the second property, a method to prove that a given signature is a forgery.
Digital signature
A digital signature or digital signature scheme is a mathematical scheme for demonstrating the authenticity of a digital message or document. A valid digital signature gives a recipient reason to believe that the message was created by a known sender, and that it was not altered in transit...
invented by David Chaum
David Chaum
David Chaum is the inventor of many cryptographic protocols, including blind signature schemes, commitment schemes, and digital cash. In 1982, Chaum founded the International Association for Cryptologic Research , which currently organizes academic conferences in cryptography research...
and Hans van Antwerpen in 1989. They have two distinctive features,
- The verification process is interactive, so that the signatory can limit who can verify the signature.
- A disavowal protocol, which is a cryptographic protocolCryptographic protocolA security protocol is an abstract or concrete protocol that performs a security-related function and applies cryptographic methods.A protocol describes how the algorithms should be used...
that allows them to determine whether a given signature is a forgeryForgeryForgery is the process of making, adapting, or imitating objects, statistics, or documents with the intent to deceive. Copies, studio replicas, and reproductions are not considered forgeries, though they may later become forgeries through knowing and willful misrepresentations. Forging money or...
.
The first means that a signatory can allow only others who are authorized to access the document to verify their signature. If the document were to be leaked to a third party, the third party would be unable to verify that the signature is genuine. This is a designated verifier signature
Designated verifier signature
A designated verifier signature is a signature scheme in which signatures can only be verified by a single designated verifier who is chosen by the signer. Designated verifier signatures were first proposed in 1996 by Jakobsson Sako, Kazue Sako, and Russell Impagliazzo...
.
However, because of this property it means that the signatory may deny a signature which was valid. To prevent this, there is the second property, a method to prove that a given signature is a forgery.