ISSN(Online): 2320-9801 ISSN (Print): 2320-9798 International Journal of Innovative Research in Computer and Communication Engineering (An ISO 3297: 2007 Certified Organization) Vol. 2, I ssue 4, April 2014 Copyright to IJIRCCE www.ijircce.com 4104 Taxonomy of E-Mail Security Protocol Ankur Dumka, Ravi Tomar, J.C.Patni, Abhineet Anand Assistant Professor, Centre for information Technology, University of Petroleum and Energy Studies,Dehradun, India ABSTRACT - The Email messaging is one of the most popular uses of the internet & the multiple internet user can exchange messages within short span of time using To (Original recipient), Cc (Carbon copy) and /or Bcc (Blind Carbon Copy) Facilities. Thus Email becomes the most popular application on the internet. It is also by far the most popular application on intra company networks. Securing e-mail is something that must be done by the users themselves, because they are the ones who will actually be sending & receiving the messages. However, security administrators can gives user the tools they need to be fighting the problems. S/MIME, PGP &PEM are very popular methods of encrypting e-mail .Email users need to be educated about security though because the popularity & functionality of e-mail is only going to increase. KEYWORDS - PGP, PEM, S/MIME, SMTP, Cryptographic function I. INTRODUCTION Email is quite arguably the most important application for personal & business communication across the internet. People depend on it for sending text, image & even sound files to destinations .This is a far cry from the postal service & even the pony express for delivering the messages to their destination in days & weeks. Email was designed to be both easy to use & quick for fast end to end message delivery. Consequently, the security of email message has become an extremely important issue. Securing email is something that must be done by the user themself, because they are the one who will actually be sending & receiving the messages. However security administrators can give users the tools they need to fight the problems. Server based & desktop based virus protection can help against malicious code, & spam filters attempt to block all unsolicited commercial e-mail. E-mail users need to be educated about security, though, because the popularity & functionality of e-mail is only going to increase. The goal of Email security will be to provide secure method for sending & receiving email over the internet. This will include both service provider technologies, as well as, end user client solutions to encompass E-mail technology as whole. The security protocol must encapsulate an essential set of cryptographic function .The security protocol support three cryptographic functions. Encryption: The process of encoding plain text message into cipher text message is called as encryption. Non-Repudiation: Provide protection against denial by one of the entities included in a communication of having participated in all or part of the communication., Non-Repudiation, Origin: Proof that a message was sent by the specified party. Non-repudiation, Destination: Proof that the message was received by the specified party. Integrity: The transmitted message is never altered. The assurances that message received are exactly as sent by an authorized entity. To ensure the e-mail security all these cryptographic function must implement with in a security protocol. There are three e-mail security protocols.