Re: [Cfrg] KangarooTwelve draft has been updated to 01

[Benoît Viguier <[e-mail]>]

Hi David,

Using their names directly as variables breaks the compactness of the 
writing. cf as follows:

S = M || C || length_encode( |C| ) KangarooTwelve( M, C, L ) = F( 
FinalNode||`07`, L ) KangarooTwelve( M, C, L ) = F( FinalNode||`06`, L )

Also with the same arguments we should expend L.
Also the following text is quite explicit about the meaning of M and C :

KangarooTwelve is an eXtendable Output Function (XOF). It takes as an 
input a couple of byte-strings (M, C) and a positive integer L where M 
byte-string, is the Message and C byte-string, is a OPTIONAL 
Customization string and L positive integer, the number of output bytes 
requested.

In the end those are mainly editorial details.

On 01/22/2018 04:20 PM, David Wong wrote:
>> While the notation X, S by NIST SP - 800-185, I find Message and
>> Customization string easier to remember:
>> variable names should be able to give the reader an idea of what they are
>> about. Also NIST FIPS 180-4 and NIST FIPS 202 uses M for message. However if
>> a majority of people are in favor of (X,S), I don't mind switching for this
>> notation.
> By the way, why not giving them actual names like "custom_string" and "message"?
>
> David

-- 
Kind regards,

Benoît Viguier
Software Engineer - PhD Student | Cryptography & Formal Methods
Radboud University | Mercator 1, room 03.17, Toernooiveld 212
6525 EC Nijmegen, the Netherlands | www.viguier.nl