DES (Data Encryption Standard). A fairly weak
encryption technique using 56-bit keys. It uses the same key to encrypt as to
decrypt. There is only the private key, which both sender and receiver must know,
unlike PGP (Pretty Good Privacy) and digital certificate encryption, which uses a public key to encrypt and
a private key to decrypt and a private key to digitally sign and a public key to
verify the signature. A personal computer could crack DES-encoded message within a
year; a group of them could do it proportionately faster. Presumably, the
CIA (Central Intelligence Agency) has special purpose hardware for doing it in seconds.
The advantage DES has over public key encryption is that it is much
faster to compute. US law prohibits export of DES
code with more than 64-bit keys.