Explanation/Reference:
Explanation:
E-mail encryption solutions such as S/MIME have been available for a long time. These encryption solutions have seen varying degrees of adoption in organizations of different types. However, such solutions present some challenges:
Inability to apply messaging policies: Organizations also face compliance requirements that require inspection of messaging content to make sure it adheres to messaging policies. However, messages encrypted with most client-based encryption solutions, including S/MIME, prevent content inspection on the server. Without content inspection, an organization can't validate that all messages sent or received by its users comply with messaging policies.
Decreased security: Antivirus software is unable to scan encrypted message content, further exposing an organization to risk from malicious content such as viruses and worms. Encrypted messages are generally considered to be trusted by most users, thereby increasing the likelihood of a virus spreading throughout your organization.
Incorrect Answers:
B: Virus scanning and content inspection of S/MIME encrypted e-mail is not possible even with a key recovery scheme of all user keys.
C: Virus scanning and content inspection of S/MIME encrypted e-mail is not possible even if X509 Version
3 certificates are used.
D: Using "brute force" decryption on S/MIME encrypted e-mail for the purpose of virus scanning and content inspection is not practical and unlikely to be successful.
References:
https://technet.microsoft.com/en-us/library/dd638122(v=exchg.150).aspx