CHAPTER ONE
INTRODUCTION
Data encryption description system (DEDS) is an important aspect of any system. Data encryption description system is the act of ensuring that an authenticated user accesses only what they are authorized to and no more. The bad news is that security is rarely at the top of people’s lists, although mention terms such as data confidentiality, sensitivity, and ownership and they quickly become interested. The good news is that there is a wide range of techniques that you can apply to help secure access to your system. Three of the most popular cryptography systems used are the Data Encryption Standard (DES), Pretty Good Privacy (PGP), and the Rivest, Shamir, Adleman (RSA) system. DES uses a single key for both encrypting and decrypting. It was developed by International Business Machines Corporation (IBM) and approved by the United States National Institute of Standards and Technology in 1976. PGP is an encryption system that also uses two keys. It is based on the RSA algorithm. PGP was invented by software developer Philip Zimmerman and is one of the most common cryptosystems used on the Internet because it is effective, free, and simple to use. PGP is such an effective encryption tool that the United States government sued Zimmerman for releasing it to the public, alleging that making PGP available to enemies of the United States would endanger national security. The lawsuit was dropped, but it is still illegal in some countries to use PGP to communicate with people in other countries. In the two-key system, also known as the public key system, one key encrypts the information and another, mathematically related key decrypts it. The computer sending an encrypted message uses a chosen private key that is never shared and so is known only to the sender. All computers authorized to receive and decrypt the message are given the matching public key. This method also establishes who sent the message. If a sending computer first encrypts the message with the intended receiver’s public key and again with the sender’s secret, private key, then the receiving computer may decrypt the message, first using its secret key and then the sender’s public key.
Using this public-key cryptographic method, the sender and receiver are able to authenticate one another as well as protect the secrecy of the message. Single key methods, in contrast, require great secrecy in conveying a key from sender to recipient. The length or complexity of the key (along with the difficulty of the algorithm) usually indicates the effectiveness of the encryption. DES, for example, uses 56 bits in its key to change 8-character message segments into 64-bit segments of ciphertext. In 1997 the National Institute of Standards and Technology began coordinating development of a new encryption system called Advanced Encryption Standard (AES). AES is to replace DES, as it will use a stronger algorithm, based on a 128-bit encryption standard instead of the 64-bit standard that DES now uses. Another advanced encryption system employs the International Data Encryption Algorithm, or IDEA, based on 128-bit segments. The Swiss Federal Institute of Technology developed the IDEA standard in the 1990s. Banks in the United States and several countries in Europe use the IDEA standard for many of their transaction
