What is the purpose of non-repudiation in information security?

Non-repudiation ensures that an individual or system cannot deny having performed a specific action, such as sending or receiving a message or approving a transaction. It provides proof of origin and proof of delivery.

This security principle is typically implemented using cryptographic techniques such as digital signatures, public key infrastructure (PKI), hashing, and secure audit logs. For example, a digitally signed message can later be verified, preventing the sender from denying authorship.

Non-repudiation supports accountability, legal enforceability, and forensic investigations. It differs from confidentiality (preventing unauthorized access), integrity (preventing unauthorized modification), and availability (ensuring access).

Non-repudiation is especially important in financial systems, legal communications, and regulated industries where disputes may arise.