List maintained by Douglas Stinson and Ruizhong Wei.

A detailed discussion of cryptographic nonlinearity, what it means and how it is computed, with active JavaScript panels to perform the computation.

An interesting paper by Ron Rivest about providing confidentiality without encryption.

Oded Goldreich. A public domain book available on-line. Only partially completed.

A research tool for the cryptography community maintained by Counterpane Systems. Over 400 papers online.

Lecture notes for a course on cryptography and number theory.