Non-repudiation ensures that an entity cannot deny having performed a specific action, such as sending a message, approving a transaction, or signing a document. Cryptographic digital signatures are central to non-repudiation: they bind the content of a message or file to the identity of the signer in a verifiable way. For example, in e-commerce or legal contracts, a digitally signed document can be independently verified to confirm who signed it and that it has not been altered since signing. Without non-repudiation, disputes over transactions or communications would be far more difficult to resolve.