Lamport's Hash

From Network Security: Private Communication in a Public World 2nd Edition, p225:

"Without public key cryptography, it's difficult to protect against both eavesdropping and server database reading with a single protocol, although is is easy to do one or another...an elegant protocol by Leslie Lamport can claim to accomplish this feat."

Published in 1981, implemented as S/KEY by Haller et al in 1994, and standardized as RFC 1938 in 05-1996.