Which method provides non-repudiation in encryption?

Non-repudiation in encryption refers to a method that ensures that a party cannot deny the authenticity of their signature or the transmission of a message. Asymmetric encryption and hashing together provide a robust mechanism for achieving non-repudiation.

Asymmetric encryption uses a pair of keys (a public key and a private key) where the public key can be shared openly while the private key is kept secret. When a message is encrypted with a sender's private key, only the corresponding public key can decrypt it, thereby allowing the recipient to verify that the message indeed came from the sender. This serves as a proof that the sender cannot later deny sending the message, hence ensuring non-repudiation.

Hashing complements this process by creating a unique fixed-length input (the hash) from the original data. When combined with asymmetric encryption, the hash of the message can be digitally signed using the sender's private key. This allows the recipient to confirm both the integrity of the message and the identity of the sender since only the sender has access to the private key.

Other methods do not inherently provide the same guarantee of non-repudiation. For instance, symmetric encryption uses the same key for both encryption and decryption, which means both parties hold