Cryptography. The very name conjures up images of secrecy and spying, with project code names like "Magic" and "Lucifer." And indeed until fairly recently data encryption was a shrouded capability, used almost exclusively by military and diplomatic organizations. The computerization of information processing and transmission has changed this. In response to a growing commercial need, the National Bureau of Standards has promulgated a national Data Encryption Standard, developed by IBM. The standard, called DES, can be implemented in software or on a single LSI chip and can be used with any computer to encrypt and decrypt transmitted data. A single-chip version should sell for about $10 in quantity production. But just how good is the protection offered by DES?