Mime/Smime

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MIME/SMIME

In its most primitive, text-only form, e-mail is a powerful communications tool for both businesses and consumers. The ability to add picture, audio, and video attachments makes it even more powerful—especially for e-marketers. Multipurpose Internet Mail Extensions (MIME) allow these many different kinds of files to be exchanged online. MIME is an extension of the Simple Mail Transfer Protocol (SMTP), which specifies the format of e-mail messages. Originally, MIME was created to send ASCII text files. However, it evolved to support the many different types of files that were being widely used for e-commerce.

MIME works through the use of headers, which servers (computers used to host Web sites, e-mail systems, or applications) insert into all mail transmissions as they are sent. Client applications like Web browsers or e-mail programs are then able to read the information contained in the headers and determine what kind of file has been sent and how to display or run a file's contents. MIME supports a large number of different file types in the realms of video, audio, images, text, and application files. Among these many file types are JPEG, TIFF, GIF, Postscript, MPEG, and QuickTime files.

Before it became a standard, MIME was first proposed to the Internet Engineering Task Force (IETF) in the early 1990s by Bellcore's Nathan Borenstein. The IETF is "a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet." A secure version of MIME, called S/MIME, allows messages to be encrypted between sender and receiver. S/MIME relies on a form of encryption called Rivest-Shamir-Adleman, created by Redwood City, California-based RSA Data Security Inc. Encryption is a process that allows messages to be sent securely from one party to another, and intends to prevent unauthorized parties from reading the message's contents.

Despite the increased capabilities MIME provides to e-mail users, it is not universally popular. In Network World, Scott Bradner of Harvard's University Information Systems department called the standard annoying, and criticized it for causing problems with message readability and size, as well as software compatibility. Bradner pointed out that if the receiving party to a message does not have the right software application for opening and viewing a file, the receiver receives a file filled with garbled text, which can be both frustrating and confusing.