From 99ad9689e92eabeef5d1a7447f53c1173bb9ba2b Mon Sep 17 00:00:00 2001 From: Daira Hopwood Date: Mon, 12 Feb 2018 13:10:14 +0000 Subject: [PATCH] Generalize Pedersen hash spec to make chunks per segment variable. Signed-off-by: Daira Hopwood --- protocol/protocol.tex | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/protocol/protocol.tex b/protocol/protocol.tex index 4910eb75..cc48c55d 100644 --- a/protocol/protocol.tex +++ b/protocol/protocol.tex @@ -3657,19 +3657,22 @@ Let $\ExtractJ$ be as defined in \crossref{concreteextractorjubjub}. Let $\FindGroupJHash$ be as defined in \crossref{concretegrouphashjubjub}. +Let $c = 63$. + \newsavebox{\gencountbox} \begin{lrbox}{\gencountbox} \begin{bytefield}[bitwidth=0.28em]{32} - \bitbox{32}{$32$-bit $\floor{\frac{i-1}{61}}$} + \bitbox{32}{$32$-bit $\floor{\frac{i-1}{c}}$} \end{bytefield} \end{lrbox} \introlist +\vspace{2ex} Define $\PedersenBaseAlg, \PedersenGenAlg \typecolon \byteseq{8} \times \Nat \rightarrow \GroupJ$ by: \begin{tabular}{@{\hskip 2em}r@{\;}l} $\PedersenBase{D}{i}$ &$:= \FindGroupJHash\left(D, \Justthebox{\gencountbox}\right)$ \\ - $\PedersenGen{D}{i}$ &$:= \scalarmult{4 \smult ((i\!-\!1) \bmod 61)}{\PedersenBase{D}{i}}$ + $\PedersenGen{D}{i}$ &$:= \scalarmult{4 \smult ((i\!-\!1) \bmod c)}{\PedersenBase{D}{i}}$ \end{tabular} \newcommand{\si}[1]{s^{\kern 0.02em i}_{#1}}