S/MIME (Secure / Multipurpose Internet Mail Extensions) is a standard for public key encryption and signing of e-mail encapsulated in MIME. S/MIME is similar to OpenPGP and older PGP/MIME , but incompatible with those.

External links

• S/MIME working group charter — has links to S/MIME related RFCs and internet drafts.
• How to forge an S/MIME signature — critique on some S/MIME implementations.
• S/MIME IETF Working Group
• S/MIME and OpenPGP