An industry-standard code that defines how an e-mail message is sent in code and then decoded when received at its destination. It is actually a protocol for e-mail that enables the transmission of non-text data, such as graphics, audio, video, and other binary types of files. These files are encoded into text that would look like gobbledygook to us.
An e-mail program, such as Eudora, is MIME-compliant if it can send and receive files using the MIME standard. The MIME standard is universally used by Internet servers to identify the files that are sent to clients. Since the files are identified by the servers, users can accommodate new file formats by adding them to their browser's list of MIME-types and programs for handling each type. S/MIME, the secure version of the standard, utilizes an encryption system to protect e-mail, even when it is sent between different e-mail clients. S/MIME messages include the message itself and the encryption information (such as a digital certificate).