CompTIA Security+

Answer: A - Secure Multipurpose Internet Mail Extensions (S/MIME) is a standard used for encrypting e-mail. S/MIME contains signature data. It uses the PKCS #7 standard (Cryptographic Message Syntax Standard) and is the most widely supported standard used to secure e-mail communications.

Key Takeaway: S/MIME is a standard for public key encryption and signing of e-mail encapsulated in MIME. It provides the cryptographic security services which include authentication, message integrity, and non-repudiation of origin, privacy, and data security.