What are MIME and S/MIME?

Multi-purpose Internet Mail Extensions (MIME) is a standard first defined in 1992 to extend the capabilities of Internet email beyond plain ASCII text.

S/MIME, the secure version of the MIME protocol, supports message encryption based on RSA's public key encryption technology. (PGP is another example of public key technology.)

The MIME standard includes:

• Specifications for character sets other than US-ASCII
  
  
• A defined set of content types (such as image, audio, and application types)
  
  
• A way to encapsulate several different objects (such as attachments) within a single message
  
  
• Standard encoding methods such as Base64 and quoted-printable
  
  
• Extended mail headers for specifying character sets, content types, message parts, and encoding

Although MIME was originally designed for email, web browsers also use MIME content types to identify multimedia files so they can launch the appropriate plug-ins for retrieving audio, video, or other non-HTML materials.

For more, see:

Also see:

• At IU, what email systems are available?
• In MIME, what is the quoted-printable encoding method?
• What are character sets?
• On the IU central systems, can I specify the MIME type of files linked on my web page?
• What is an "application/octet-stream" MIME attachment, and how can I see it?
• How do I obtain an S/MIME certificate for my email client?