Document Type Replaced Internet-Draft (cfrg RG)
Author Benoît Viguier 
Last updated 2019-03-13 (latest revision 2019-02-07)
Replaced by draft-irtf-cfrg-kangarootwelve
Stream Internet Research Task Force (IRTF)
Intended RFC status (None)
Expired & archived
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Stream IRTF state Replaced
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IESG IESG state Replaced by draft-irtf-cfrg-kangarootwelve
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document defines the KangarooTwelve eXtendable Output Function (XOF), a hash function with output of arbitrary length. It provides an efficient and secure hashing primitive, which is able to exploit the parallelism of the implementation in a scalable way. It uses tree hashing over a round-reduced version of SHAKE128 as underlying primitive. This document builds up on the definitions of the permutations and of the sponge construction in [FIPS 202], and is meant to serve as a stable reference and an implementation guide.


Benoît Viguier (b.viguier@cs.ru.nl)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)