You will recall that PGP generates two keys at a time (a keypair) that are complementary: what one key encrypts, the other decrypts - and vice versa. One of the keys is made public; the other is kept secret by its user. This asymmetric encryption algorithm makes possible the public-key crypto-system, and that is very useful indeed.
Read more at Net-Security.org.. -Mirko Zorz
November 21, 2000