Which concept refers to the inability to deny that a message was sent and its integrity remains intact?

• A. Privacy Shield
• B. Non-repudiation
• C. Risk
• D. Regulations

Answer: (B)

Non-repudiation is the guarantee that a party cannot deny having sent a message and that the message’s content has not been altered. In practice, this is achieved with cryptographic signatures and tamper-evident logs: a sender signs the message with a private key, and anyone with the corresponding public key can verify the signature and the message hash to confirm both who sent it and that it hasn’t been changed. Timestamps and secure audit logs can add further evidence, making it difficult for the sender to dispute the transmission or the integrity of the content. Privacy Shield concerns data privacy and cross-border transfers, while risk and regulations describe potential threats and rules, not the assurance that a sender cannot repudiate and that the message remains intact.