Non-repudiation

Non-repudiation

In law, Non-repudiation is a situation where a statement's author cannot successfully dispute its authorship or the validity of an associated <a href="/en/Contract" title="Contract" class="wl">contract</a>.<a href="#cite_note-1" style="counter-reset: mw-Ref 1;">[1]</a> The term is often seen in a legal setting when the authenticity of a signature is being challenged. In such an instance, the authenticity is being "repudiated".[<a href="/en/Wikipedia:Citation_needed" title="Wikipedia:Citation needed" class="wl">citation needed</a>]

<div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none" about="#mwt1">Legal term</div>
For example, Mallory buys a cell phone for $100, writes a paper <a href="/en/Cheque" title="Cheque" class="wl">cheque</a> as payment, and <a href="/en/Signature" title="Signature" class="wl">signs</a> the cheque with a pen. Later, she finds that she can't afford it, and claims that <a href="/en/Cheque_fraud" title="Cheque fraud" class="wl">the cheque is a forgery</a>. The signature guarantees that only Mallory could have signed the cheque, and so Mallory's bank must pay the cheque. This is non-repudiation; Mallory cannot repudiate the cheque. In practice, pen-and-paper signatures aren't hard to <a href="/en/Signature_forgery" title="Signature forgery" class="wl">forge</a>, but <a href="/en/Digital_signatures" title="Digital signatures" class="mw-redirect wl">digital signatures</a> can be very hard to break.

In law, Non-repudiation is a situation where a statement's author cannot successfully dispute its authorship or the validity of an associated contract. For example, Mallory buys a cell phone for $100, writes a paper cheque as payment, and signs the cheque with a pen.  Later, she finds that she can't afford it, and claims that the cheque is a forgery.  The signature guarantees that only Mallory could have signed the cheque, and so Mallory's bank must pay the cheque.  This is non-repudiation; Mallory cannot repudiate the cheque. In practice, pen-and-paper signatures aren't hard to forge, but digital signatures can be very hard to break. 