As a cybersecurity consultant for SafePath Corp, you have been tasked with implementing a system for secure email communication. The key requirement is to ensure both confidentiality and non-repudiati

RSA asymmetric encryption satisfies both requirements simultaneously: the sender signs the message with their private key (only they possess it), providing non-repudiation since the signature can be verified by anyone with the public key, while the recipient's public key encrypts the message content to ensure confidentiality. This dual use of asymmetric cryptography is the foundation of secure email protocols like S/MIME and PGP.

Diffie-Hellman is a key exchange protocol used to establish a shared secret over an insecure channel, but it does not provide encryption itself nor does it inherently support digital signatures for non-repudiation.

Using only the public key for encryption addresses confidentiality but does not provide non-repudiation, because anyone with access to the recipient's public key could have sent the encrypted message, making the sender's identity unverifiable.

Symmetric encryption with AES provides confidentiality but cannot fulfill non-repudiation requirements because the same shared key is held by both parties, meaning either party could have encrypted the message and neither can prove sole authorship.