An online stock trading firm is in the process of implementing a system to provide secure e-mail exchange with its customers. What is the BEST option to ensure confidentiality, integrity and nonrepudiation

D. Digital certificates

Explanation:

Digital certificates are the only option which offers confidentiality, integrity and nonrepudiation. These certificates contain both a public and private key. More importantly, these certificates are backed up by a trusted authority, which issues them to firms. Confidentiality and integrity aspects are respected by the existence of both the public and private key encryption. The nonrepudiation is fulfilled by the secured recognition of the third party authority.