What mechanism is used to ensure that a sender cannot deny sending a message?

The mechanism that ensures a sender cannot deny sending a message is known as non-repudiation. This concept is critical in cybersecurity and involves methods that provide evidence of the origin, delivery, and integrity of a message. Non-repudiation is typically achieved through the use of cryptographic techniques such as digital signatures, which link a unique identifier to the sender, thus creating a legal binding contract that the sender cannot later deny.

When a sender signs a message with a private key, onlookers, or recipients, can verify the signature using the sender's public key. This verification process confirms both the identity of the sender and that the message has not been altered during transit. Consequently, if any dispute arises, the evidence of the signature can be presented, thereby preventing the sender from claiming they did not send the message.

In contrast, encryption focuses on obscuring the content of a message, thus making it unreadable to unauthorized parties, but it does not inherently provide proof of sending. Authentication verifies the identity of a user or system but does not prevent denial of action, which falls outside its scope. Authorization deals with permissions and access control but does not directly relate to the acknowledgment of message sending. Non-repudiation combines elements of authentication and