Antonio Nicolosi Stevens Institute TITLE: Encrypted key exchange: password-based protocols secure against dictionary attacks ABSTRACT: Classical cryptographic protocols based on user-chosen keys allow an attacker to mount password-guessing attacks. We introduce a novel combination of asymmetric (public-key) and symmetric (secret-key) cryptography that allow two parties sharing a common password to exchange confidential and authenticated information over an insecure network. These protocols are secure against active attacks, and have the property that the password is protected against off-line "dictionary" attacks. There are a number of other useful applications as well, including secure public telephones. Authors: S. M. Bellovin and M. Merritt