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Issue 5.6



Vernam Cipher and E-mail

Issue: 5.6 (September/October 2007)
Author: JC Cruz
Author Bio: JC is a freelance technical writer living in British Columbia. He writes for various publications, pokes around with Cocoa and REALbasic, and spends time with his nephew. He can be reached at anarakisware@gmail.com.
Article Description: No description available.
Article Length (in bytes): 33,061
Starting Page Number: 23
Article Number: 5610
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Download Icon 5610.zip Updated: 2013-03-11 19:08:00

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Excerpt of article text...

In this article, we will look into the topic of e-mail encryption. First, we will learn the basics of an e-mail system. Then we will learn the security issues that plague such a system. Next, we will develop two custom classes that use the Vernam cipher to encrypt a message. Finally, we will use these classes to send and receive an encrypted message.

A Quick E-mail Primer

Since 1961, e-mail became one of the most common forms of communication. It evolved from a way of exchanging written text to one that delivers pictures, sound, and even software.

Most e-mail systems work as client-server systems (Figure 1). The e-mail client sends a message to the mail server. If the recipient is on the same server as the sender, the server sends a copy of the message to the recipient. Otherwise, the server routes the message to the other servers on the network.

Also, most e-mail systems support at least two basic protocols to handle message exchange. Clients send messages to the server using SMTP. They then retrieve messages from the server using POP3 or IMAP.

The Simple Mail Transfer Protocol

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