S/MIME
Secure/Multipurpose Internet Mail Extensions
A standard for signing and encrypting email using certificates.
S/MIME uses X.509 certificates and a public key infrastructure to sign and encrypt email, providing confidentiality, integrity, authentication, and nonrepudiation. Signing proves the sender's identity and that the message was not altered, while encryption protects the body from being read in transit or at rest. It contrasts with transport protections like STARTTLS, which only secure the hop between servers, and with PGP, which relies on a web of trust rather than hierarchical certificate authorities.
Looking S/MIME up is step one. Getting tested on it is step two.
A free account opens all 4 Domain 1 objectives, 271 exam-style questions with a lesson and a lab on each, a placement check that skips what you already know, and a dated plan. No card.
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