QuickCrypt Library

DES Overview

DES (Data Encryption Standard) is the most well-known symmetric-key block cipher algorithm. Recognized world-wide, it set a precedent in the mid 1970s as the first commercial-grade modern algorithm with openly and fully specified implementation details. It is defined by the American standard FIPS 46-3.

DES is a block cipher; it encrypts data in 64-bit blocks. A 64-bit block of plaintext goes in one end of the algorithm and a 64-bit block of ciphertext comes out the other end. DES is a symmetric algorithm: The same algorithm and key are used for both encryption and decryption (except for minor differences in the key schedule). 

A DES key consists of 64 binary digits ("0"s or "1"s) of which 56 bits are used directly by the algorithm. The other 8 bits, which are not used by the algorithm, may be used for error detection. The 8 error detecting bits are set to make the parity of each 8-bit byte of the key odd, i.e., there is an odd number of "1"s in each 8-bit byte.

CDES Overview   |   DES API Overview   |   Useful Links

See Also    QuickCrypt Library Overview