Yarrow

Pseudorandom number generation is a foundation of cryptography, so choosing the right algorithm for generating these numbers is very important. The Yarrow design is described in "Yarrow-160: Notes on the Design and Analysis of the Yarrow Cryptographic Pseudorandom Number Generator" by John Kelsey, Bruce Schneier and Niels Ferguson of Counterpane Systems, available from http://www.counterpane.com/yarrow.html. This implementation is provided under the terms of the BSD license, and allows unrestricted use, modification, and redistribution of the code and derived binaries. Please see the LICENSE file for more details.

It is Zero-Knowledge's hope that third party developers of yarrow will collaborate to derive test vectors. In an effort to further this discussion, we have created a mailing list for developers and interested parties. To subscribe, send an email to yarrow-request@zeroknowledge.com with "subscribe" in the body of the message.

Developers should note that, until there are acceptable test vectors available, this implementation of yarrow should not be used in a production environment.

Source code

Donwload zkyarrow-0.01.tar.gz.

Browse the source code:

• ASSUMPTIONS
• LICENSE
• README
• TODO
• yarrow(3) manpage
• src/
  • yarrow.c
  • yarrow.h
  • ycipher.h
  • yexcep.h
  • yhash.h
  • ylock.h
  • yseed.c
  • ystate.c
  • ystate.h
  • ytest.c
  • ytypes.h

Other Yarrow implementations

• An implementation of the Yarrow PRNG in Java (source)
• Yarrow in Python, part of an SPKI implementation (download)
• An implementation for the FreeBSD randomness device
• A C++ implementation by Christian Thöing (incomplete)
• An older version of Yarrow for Win32 by Ari Benbasat

• An implementation by the Reliable Software Technologies Corporation
• A Delphi implementation by Marcel Popescu

Zero-Knowledge Systems has not evaluated these implementations.

Publications on cryptographic PRNGs

J. Kelsey, B. Schneier, and N. Ferguson: Yarrow-160: Notes on the Design and Analysis of the Yarrow Cryptographic Pseudorandom Number Generator

P. Gutmann: Software Generation of Practically Strong Random Numbers

D. Wagner: Randomness for crypto