What it is
Non-repudiation is a core information security principle that guarantees the authenticity and integrity of data by preventing parties from denying their actions. It ensures that once a transaction, message, or digital signature has been created, the sender cannot later dispute its origin or validity.
Cryptographic mechanisms such as digital signatures, public key infrastructure (PKI), and secure audit logs underpin non-repudiation. When a message is signed using a private key, only the holder of that key could have produced it. Verification with the corresponding public key confirms its authenticity and integrity. Coupled with timestamping and secure logging, non-repudiation creates an auditable trail for accountability.
Why it matters
In legal and financial systems, non-repudiation underpins trust in digital transactions. Electronic contracts, online payments, and even blockchain transactions depend on this property to enforce accountability. Without non-repudiation, disputes about authorship or consent would erode confidence in e-commerce, digital governance, and secure communications.
How to reduce risk
- Use digital signature frameworks that meet recognized standards such as X.509 or PGP.
- Employ timestamping authorities to verify when signatures occur.
- Protect private keys using hardware security modules.
- Ensure audit logs are immutable and cryptographically signed.
- Implement strong identity verification during key issuance.