5 Examples of Non-repudiation

John Spacey, updated on December 23, 2016

Non-repudiation is the ability to prove or disprove that something happened such as a financial transaction or a binding signature on a legal agreement. It has its roots in legal processes intended to prevent entities from claiming they didn't agree to something or sign a document. In its modern form, it is both a legal and technology concern. The following are illustrative examples of non-repudiation.

Notary

It is common for the signing of legal documents to be witnessed by a licensed notary. The notary ensures that the signature is authentic and not made under the undue influence of a third party.

Forensic Science

A handwriting expert may be used by a legal service as a means of non-repudiation of signatures.

Authentication

A user is authenticated according to multiple factors before performing a financial translation on a banking website. This makes it more difficult for the user to dispute a transaction such as a stock trade.

Audit Trail

A financial website maintains a detailed record of each page visited including information such as IP addresses. This information can be used in digital forensics to prove the authenticity of a user action.

Digital Signatures

A ecommerce retailer accepts invoices from a supplier electronically using an integration interface. The interface authenticates the partner by confirming that they can decrypt a message that was encrypted using the public key found in the partner's digital certificate. This involves sending an encrypted hashcode and requiring the partner to decrypt it and send it back. An audit trail is created that includes the unique hashcode that was decrypted by the partner. The only way that the partner can realistically claim the transaction didn't happen to to claim their private key was compromised.

Overview: Non-repudiation
Type	Information Assurance Compliance Law Information Security
Definition	The ability to prove or disprove that something happened such as a financial transaction or legally binding signature.
Value	A cornerstone of law, commerce and information security.
Related Concepts	Information Security Audit Trail Authentication Hashcode Cryptography Information Assurance