As i am pursuing my engineering course from the field of Information Technology, i thought of writing something related to my field. Electronic mail, commonly referred as emails is the method of exchanging information in a standard format from creator to the receiver. Email is the most widely used application on internet today, whether it be for business or personal purposes.
Email system works on the store and forward technique which allows the sender to send any message to its destination without asking the receiver of the message to be online at that time. Earlier the email system required both the parties to be online when the messages were to be transferred. Internet today has become a frontier of various kinds of elements, including softwares, business information exchange and many more.
Two schemes extensively used for securing emails are PGP(Pretty Good Privacy) and PEM(Privacy Enhanced Email). Developed by Phil Zimmerman, pretty good privacy provides authentication, privacy, confidentiality to emails. Also it addresses various issues of compression required in emails.
The main mechanism involved in PGP is as follows. Suppose A is the sender and B is the receiver of any digital content which is to be sent online. If A wants to securily send any data to B then y making use to private and public keys of both A and B it can be done. First the message from the sender is hashed through MD5 and then it is encrypted with A’s(sender) private key. Now this encrypted hash message is combined with the original message to be sent. After this the combined message is zipped. Now the PGP program will ask A to enter any random input which is used to generate a 128 bit IDEA key. Now this key is used to encrypt the output which came after the message was zipped.
The other scheme i mentioned Privacy Enhanced Mail(PEM) is commonly used in conjunction with Simple Mail Transfer Protocol. Disclosure protection, Integrity of messages sent, authenticity of the originator etc are some functions provided by PEM. Messages sent through PEM are converted into canonical form first which ensures that message transfer agents used are not entitled to modify them.