Encryption concepts and applications

Encryption is the translation of data into a secret code (Encryption pp). Encryption is the most effective way to achieve data security because to read an encrypted file, one must have access to a secret key or password that enables a person to decrypt it (Encryption pp). Unencrypted data is called plain text, while encrypted data is referred to as cipher text (Encryption pp). The two main types of encryption are asymmetric encryption (also called public-key encryption), and symmetric encryption (Encryption pp).

Symmetric encryption is where the same key is used to encrypt and decrypt the message (Symmetric pp). This differs from asymmetric or public-key encryption that uses one key to encrypt a message and another to decrypt the message (Symmetric pp).

An Asymmetric encryption is a cryptographic system that uses two keys, a public key known to everyone and a private or secret key known only to the recipient of the message (Public pp). For example, "when John wants to send a secure message to Jane, he uses Jane's public key to encrypt the message. Jane then uses her private key to decrypt it" (Public pp).

An important element to the public key system is that the public and private keys are related in such a way that only the public key can be used to encrypt messages and only the corresponding private key can be used to decrypt them. Moreover, it is virtually impossible to deduce the private key if you know the public key" (Public pp)

Public-key systems are becoming popular for transmitting information via the Internet because they are extremely secure and relatively simple to use (Public pp).

The only difficulty with public-key systems is that you need to know the recipient's public key to encrypt a message for him or her, however, there are promises of a global registry of public keys from the new LDAP technology (Public pp). Public key cryptography was invented in 1976 by Whitfield Diffie and Martin Hellman, and therefore is sometime called Diffie-Hellman encryption (Public pp).

One popular technique for encrypting messages is Pretty Good Privacy, PGP, developed by Philip Zimmerman (Pretty pp). Because it is effective, easy to use and free, PGP is one of the most common ways to protect messages on the Internet (Pretty pp).

PGP is based on the public-key method, which uses two keys - one is a public key that you disseminate to anyone from whom you want to receive a message.

The other is a private key that you use to decrypt messages that you receive" (Pretty pp).

PGP is such an effective encryption tool that the United States Government actually brought a lawsuit against Zimmerman for putting it in the public domain and therefore making it available to enemies of the United States, however, after a public outcry, the government's lawsuit was dropped, yet it is still illegal to use PGP in many other countries (Pretty pp).

To encrypt a message using PGP, you need the PGP encryption package, which is available for free from a number of sources, however the official repository is at the Massachusetts Institute of Technology (Pretty pp).