KEY-BASED ENCRYPTION: Data Encryption Standard (DES)

Classic Cryptography

Key-Based Encryption

Symmetrical Key

Assymetrical Key

RSA

IDEA, RC2 and RC4

DES

Pretty Good Privacy
(PGP)

How public key works
mathematically

Glossary

Basic Concepts in Data Encryption:
Key-Based Encryption

Data Encryption Standard (DES)

DES is the Data Encryption Standard, a secret key cryptosystem defined and endorsed by the US government. DES was developed in the 1970s and first endorsed by the US government in 1977 and is in wide use today. DES is popular because it is fast, since it can be implemented in hardware. It is a block cipher with a 64-bit block size and a 56-bit key. A version of DES being used, called Triple-DES, is essentially equivalent to using DES 3 times on plaintext with 3 different keys. It is considered much safer than plain DES.

Security-wise, DES is quite a solid algorithm. However, a group of prominent cryptographers recently announced that they have shattered the security of what may be the world's most widely used data-scrambling standard by cracking a message encoded with it in 56 hours. The crack was performed with no more than an array of home-brewed computer circuit boards. The revelation that the federally developed Data Encryption Standard (DES) is susceptible to attack means much for millions of computer users who relied on the security it provides, since now, any decent company has the ability to crack DES-encoded messages within days. But the implications for government restrictions on export of what was once considered strong security technology are even greater. Current regulations allow export of encryption technology that only uses 40-bit technology in most cases. Since 56-bit technology - indefinitely stronger - now has been proven vulnerable, FBI and national security arguments that common encryption technology is too strong to let fall into the hands of off-shore terrorists and criminals now hold less truth.