Guido Bertoni3, Joan Daemen2, Seth Hoffert, Michaël Peeters1, Gilles Van Assche1 and Ronny Van Keer1
1STMicroelectronics - 2Radboud University - 3Security Pattern
25 February 2010
The Keccak sponge function family is characterized by three parameters: the bitrate r, the capacity c and the diversifier d. In the Keccak specifications we propose four instances that can be taken as functions for the four (fixed) output lengths NIST requires for SHA-3 and a variable-output-length instance, with default values for the parameters.
Whilst we are happy with our choice, there are other valid parameter choices that NIST or others may prefer. We publish a new note, in which we discuss our choice of parameters and other possible ways of using the Keccak family.