Introduction

Regardless of the efficacy of the barriers that you erect to keep others from accessing or intercepting your sensitive data, you must recognize that your barriers won't always work. Confidential files sometimes fall into the wrong hands. Thus, you need to take additional steps to ensure that when this happens, unauthorized persons will not be able to read the data even though they have it in their possession. That's where encryption comes in.

Data encryption is a concept that predates computers. The art and science of cryptography involves hiding or changing information to protect it from unauthorized persons. The word comes from the Greek word for hidden, and the ancient Greeks, as well as those in other ancient civilizations, practiced cryptographic techniques when sending important military, political, and personal messages.

Encryption "scrambles" data so that it appears to be gibberish to anyone who doesn't have the means to "unscramble," or decrypt, it. All computer data is ultimately sent or stored in binary form (as ones and zeroes).To encrypt the binary data, a mathematical procedure called an algorithm (a calculation or formula) is applied, using a variable called the key. Methods used to encrypt data are called ciphers, and the encrypted form of data is called ciphertext. To decrypt data and return it to comprehensible form, the recipient of the data must use the proper key. This might be the same key used to encrypt it (a method called symmetric encryption) or it might be...