Yarrow algorithm - Definition and Overview

The Yarrow algorithm is a cryptographically secure pseudo-random number generator. The name is taken from the yarrow plant, the stalks of which are dried and used as a randomising agent in I Ching divination.

It was designed by Bruce Schneier, John Kelsey, and Niels Ferguson of Counterpane Labs (Kelsey et. al, 1999). The Yarrow algorithm is explicitly unpatented and royalty-free; no license is required to use it. Yorrow is incorporated in Mac OS X in place of /dev/random.

An improved design from Ferguson and Schneier, Fortuna, is described in their book, Practical Cryptography.

References

• John Kelsey, Bruce Schneier, Niels Ferguson: Yarrow-160: Notes on the Design and Analysis of the Yarrow Cryptographic Pseudorandom Number Generator. Selected Areas in Cryptography 1999: pp13–33

External links

• Yarrow algorithm page (http://www.counterpane.com/yarrow.html)
• Yarrow-160: Notes on the Design and Analysis of the Yarrow Cryptographic Pseudorandom Number Generator, J. Kelsey, B. Schneier, and N. Ferguson (http://www.counterpane.com/yarrow-notes.html)