Term that can be used in the legal sense and in the crypto-technical sense. In a legal sense, someone who signs a legal paper is permitted to “repudiate” a signature that has been attributed to him or her. A forged signature is one example of repudiation; a true signature obtained under conditions of duress is another.

The term “nonrepudiation” crypto-technically means that during authentication, a service providing proof of the integrity and origin of the information can be verified by a third party at any time. Put another way, nonrepudiation means that during authentication, the information can be found to be genuine with high assurance; for this reason, chances are slim that it could be refuted afterward.

See Also: Authentication; Cryptography or “Crypto”; Signature.