MIME (sort of Multipurpose Internet Mail Extensions) is an acronym for Multipurpose Internet Mail Extensions. Its specifies how messages must be formatted so that they can be exchanged between different email systems. Its a very flexible format, permitting one to include virtually any type of file or document in an email message. Multipurpose Internet Mail Extensions messages can contain video, audio, images, text, or other application-specific data. Specifically, MIME allows mail messages to contain:
Ø Multiple objects in a single message.
Ø Text having unlimited line length or overall length.
Ø Character sets other than ASCII, allowing non-English language messages.
Ø Multi-font messages.
Ø Binary or application specific files.
Ø Images, Audio, Video and multi-media messages.
A secure version of MIME, S/MIME (Secure/Multipurpose Internet Mail Extensions), is defined to support encryption of email messages. Based on the MIME customary, its cater the subsequent cryptographical security services for messaging applications: message integrity, authentication and non-repudiation of origin, privacy and information security.
MIME standard is also converts (encodes) non-text files into text that is commonly unreadable and then, at the other end, reconverts (decodes) the files to their original form.
MIME defines five new message headers:
Ø The Content-Transfer-Encoding
MIME-Version: Any message not containing a MIME-Version: header is assumed to be associate English plaintext message and is processed per se.
The Content-Description: Header is an ASCII string telling what is in the message. This header is required therefore the recipient can recognize whether or not it's price decryption and reading the message.
The Content-Id: Header identifies the content.
The Content-Transfer-Encoding: Tells how the body is wrapped for transmission through a network that may object to most characters other than letters, numbers, and punctuation marks.
Content-Type: It specifies the nature of the message body. Seven types are defined in RFC 2045, each of which has one or more subtypes. The type and subtype are separated by a slash, as in Content-Type: video/mpeg.