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Generalize Pedersen hash spec to make chunks per segment variable. 

Signed-off-by: Daira Hopwood <daira@jacaranda.org>
This commit is contained in:
Daira Hopwood 2018-02-12 13:10:14 +00:00
parent 0325aa2fd6
commit 99ad9689e9
1 changed files with 5 additions and 2 deletions
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7
protocol/protocol.tex
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@ -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}}