Secure Email Systems

Written by Helen Glenn Court
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Sadly, secure email systems are up there in the ranks with the likes of military intelligence, jumbo shrimp, Microsoft Works, and other well-known oxymorons. The sole conceivable exception to the intelligence community's adage that any cipher can be broken was the use of Navajo in the Pacific during World War II. Email systems can be protected, encrypted, filtered, and monitored. They can be made as secure as technology permits, but that is not an absolute measurement.

The Firewall Component of Secure Email Channels

Let's look first at firewalls. These are the first line of defense--because that is what it boils down to--against hackers or unauthorized users accessing a network infrastructure. All data flowing into and out of a network pass through the firewall and is scrutinized to determine whether it meets the criteria--set by network or security administrators--to continue to its destination.

Packet filtering is one of the more common protocols on which to configure firewalls. Data is broken into packets that are sent individually and can go in any order along possibly different routes. Most wide area networks operate with packets, including the ubiquitous TCP/IP and Frame Relay systems. Proxy servers, which effectively hide the actual network address sending the data, are also common. Application gateways--used for FTP and Telnet, for example--are effective but problematic.

Encryption is another method of ensuring secure data transfer. It, of course, carries its own burden. To read encrypted data, the user must provide a password key, which unlocks and deciphers the text. Encryption can be symmetric, in which the same key is used to encode and decode the message, or asymmetric, in which one key encodes and another decodes.


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