Non-repudiation

<p>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="/facts/Contract/SkqyGj6S">contract</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".
</p><p>For example, Mallory buys a cell phone for $100, writes a paper <a href="/facts/Cheque/AmS09zUa">cheque</a> as payment, and <a href="/facts/Signature/RlWkzWMb">signs</a> the cheque with a pen.  Later, she finds that she can't afford it, and claims that <a href="/facts/Cheque_fraud/b0xwhNCx">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 are not hard to <a href="/facts/Signature_forgery/9TYusydk">forge</a>, but <a href="/facts/Digital_signatures/tY7e2pnW">digital signatures</a> can be very hard to break.
</p>

Non-repudiation open-in-new

Non-repudiation