Discusses two mathematical ideas that come from the Incan and Mayan cultures: (1) the quipus, an Incan recordkeeping tool that encoded data via a logical-numerical system on spatial arrays of colored, knotted cords; and (2) the link between recording time and counting in the Mayan culture. (MDH)

Cryptography is the science that renders data unintelligible to prevent its unauthorized disclosure or modification. Presents an application of matrices used in linear transformations to illustrate a cryptographic system. An example is provided. (17 references) (MDH)