Encryption

The process of encryption is how communications over the Internet are made inaccessible to unauthorized interception. Encryption involves scrambling the data by processing it with a mathematical algorithm that converts the communication to an unreadable string of letters and numbers. If the communication is somehow intercepted, it's impossible for the eavesdropper to interpret it. After the communication reaches its intended recipient, a similar algorithm reverts it back to its original, unencrypted form.Here's a description of the two basic types of encryption used to secure communications over the Internet. Both use the analogy of a "key" to lock and unlock communications.

Symmetric-key encryption. In symmetric-key communication, each computer involved in the communication uses a "private key," which is a type of code, to encrypt and decrypt communications. All the computers in the loop must have access to the code, and secure communication outside the network cannot take place.

For example, in symmetric-key encryption, Computer A uses its private key to encode and send a communication to Computer B, which has access to this same private key. Computer B then uses its private key to decrypt the message and, when applicable, encrypt a response that's sent back to Computer A. It's not much different than handing a written coded message to someone and then telling that person how to decipher it.

An example of symmetric-key encryption is Data Encryption Standard (DES) and its successor, Triple DES, which provides a much-greater degree of security than DES.

Public-key encryption. Public-key encryption (also called asymmetric encryption) is more commonly used than older symmetric-key encryption standards like DES because it provides for a greater level of security and encryption flexibility.

This type of encryption involves a combination of public and private keys. In this scenario, Computer A has a private key known only to itself and a public key it distributes to any other computer (Computer B), whether known to Computer A or not, that wants to communicate with it. Computer B then uses its own private key plus the public key provided by Computer A to decrypt and read the message.

The most-popular software offering public-key encryption is PGP (Pretty Good Privacy), which is a client that allows computers to encrypt and securely share e-mail messages or nearly any type of file. PGP is available from PGP Corp. at (http://www.pgp.com), and freeware and shareware versions with similar features are available elsewhere online.

Public-key encryption vs. private key. Public-key encryption is most commonly used in today's e-commerce websites because it provides a higher-degree of security for data-the chances of someone intercepting and decoding data secured with public-key encryption are amazingly miniscule. That's because today's public-key encryption products use 128-bit encryption, as opposed to the 40- and 56-bit encryption offered by public-key encryption like DES.

The higher the bit number, the greater the protection, because higher numbers mean more complex algorithms are being used. In fact, 128-bit encryption means only one of 2128 possible combinations will decipher the code. That's literally trillions of trillions of possible solutions but only one answer.