XDRGB - Random Bit Generator using any XOF

Resulting from a joint collaboration between John Kelsey (NIST), Stefan Lucks (Bauhaus-Universität Weimar, Germany) and Stephan Müller (atsec information security), a new deterministic random bit generator (DRBG) is published. The XDRBG was publicly presented at the 30th Fast Software Encryption Conference 2024 in Leuven, Belgium.

The XDRBG uses an extensible output function (XOF) as primitive which allows the use of SHAKE algorithm (FIPS 202), as well as Ascon, the finalist in the NIST lightweight cryptographic algorithm competition. In addition, other XOF functions are allowed to be used with the XDRBG specification.

The DRBG is significantly smaller compared to the DRBGs defined in SP800-90A. The XDRBG specification not only defines the algorithmic part of the XDRBG, but also provides a mathematical proof of its design. The security proof applies to all usable XOFs. In the not too far future, the XDRBG specification will also be supplemented by an appendix mapping it to the German AIS 20/31 specification. The specification also maps to the model defined in the NIST SP800-90A standard.

A standalone reference implementation is available at Github.