Suppose Alice and Bob never had a chance to meet in person, and they nevertheless want to exchange messages which will be secret from Eve. What can they do? This section discusses symmetric ciphers, a...Suppose Alice and Bob never had a chance to meet in person, and they nevertheless want to exchange messages which will be secret from Eve. What can they do? This section discusses symmetric ciphers, asymmetric ciphers, cryptographic salt, and the RSA cryptosystem.