Which concept provides non-repudiation in communications by binding the sender with the message?

• A. Digital Signatures
• B. Firewalls
• C. Due Diligence
• D. Integrity

Answer: (A)

Non-repudiation is achieved by binding the sender to the message through digital signatures. A sender signs a hash of the message with their private key, and anyone can verify the signature using the sender’s public key. This verification confirms both who created the message and that its content hasn’t been altered. Because only the private key holder could produce that signature, the sender cannot credibly deny sending the message, assuming proper key management and certificate binding. This goes beyond integrity, which only guarantees that the data hasn’t changed, not who authored it. Firewalls protect networks, not authorship of messages; due diligence is a process, not a cryptographic binding.