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fix: makes mimcsponge usable

feature/pr-19
Kobi Gurkan 5 years ago
parent
commit
9e078dc299
4 changed files with 172 additions and 0 deletions
  1. +123
    -0
      circuits/eddsamimcsponge.circom
  2. +1
    -0
      index.js
  3. +44
    -0
      src/eddsa.js
  4. +4
    -0
      src/mimcsponge.js

+ 123
- 0
circuits/eddsamimcsponge.circom

@ -0,0 +1,123 @@
/*
Copyright 2018 0KIMS association.
This file is part of circom (Zero Knowledge Circuit Compiler).
circom is a free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
circom is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for more details.
You should have received a copy of the GNU General Public License
along with circom. If not, see <https://www.gnu.org/licenses/>.
*/
include "compconstant.circom";
include "pointbits.circom";
include "mimcsponge.circom";
include "bitify.circom";
include "escalarmulany.circom";
include "escalarmulfix.circom";
template EdDSAMiMCSpongeVerifier() {
signal input enabled;
signal input Ax;
signal input Ay;
signal input S;
signal input R8x;
signal input R8y;
signal input M;
var i;
// Ensure S<Subgroup Order
component snum2bits = Num2Bits(253);
snum2bits.in <== S;
component compConstant = CompConstant(2736030358979909402780800718157159386076813972158567259200215660948447373040);
for (i=0; i<253; i++) {
snum2bits.out[i] ==> compConstant.in[i];
}
compConstant.in[253] <== 0;
compConstant.out === 0;
// Calculate the h = H(R,A, msg)
component hash = MiMCSponge(5, 220, 1);
hash.ins[0] <== R8x;
hash.ins[1] <== R8y;
hash.ins[2] <== Ax;
hash.ins[3] <== Ay;
hash.ins[4] <== M;
hash.k <== 0;
component h2bits = Num2Bits_strict();
h2bits.in <== hash.outs[0];
// Calculate second part of the right side: right2 = h*8*A
// Multiply by 8 by adding it 3 times. This also ensure that the result is in
// the subgroup.
component dbl1 = BabyDbl();
dbl1.x <== Ax;
dbl1.y <== Ay;
component dbl2 = BabyDbl();
dbl2.x <== dbl1.xout;
dbl2.y <== dbl1.yout;
component dbl3 = BabyDbl();
dbl3.x <== dbl2.xout;
dbl3.y <== dbl2.yout;
// We check that A is not zero.
component isZero = IsZero();
isZero.in <== dbl3.x;
isZero.out === 0;
component mulAny = EscalarMulAny(254);
for (i=0; i<254; i++) {
mulAny.e[i] <== h2bits.out[i];
}
mulAny.p[0] <== dbl3.xout;
mulAny.p[1] <== dbl3.yout;
// Compute the right side: right = R8 + right2
component addRight = BabyAdd();
addRight.x1 <== R8x;
addRight.y1 <== R8y;
addRight.x2 <== mulAny.out[0];
addRight.y2 <== mulAny.out[1];
// Calculate left side of equation left = S*B8
var BASE8 = [
17777552123799933955779906779655732241715742912184938656739573121738514868268,
2626589144620713026669568689430873010625803728049924121243784502389097019475
];
component mulFix = EscalarMulFix(253, BASE8);
for (i=0; i<253; i++) {
mulFix.e[i] <== snum2bits.out[i];
}
// Do the comparation left == right if enabled;
component eqCheckX = ForceEqualIfEnabled();
eqCheckX.enabled <== enabled;
eqCheckX.in[0] <== mulFix.out[0];
eqCheckX.in[1] <== addRight.xout;
component eqCheckY = ForceEqualIfEnabled();
eqCheckY.enabled <== enabled;
eqCheckY.in[0] <== mulFix.out[1];
eqCheckY.in[1] <== addRight.yout;
}

+ 1
- 0
index.js

@ -1,4 +1,5 @@
exports.smt = require("./src/smt");
exports.eddsa = require("./src/eddsa");
exports.mimc7 = require("./src/mimc7");
exports.mimcsponge = require("./src/mimcsponge");
exports.babyJub = require("./src/babyjub");

+ 44
- 0
src/eddsa.js

@ -3,12 +3,15 @@ const bigInt = require("snarkjs").bigInt;
const babyJub = require("./babyjub");
const pedersenHash = require("./pedersenHash").hash;
const mimc7 = require("./mimc7");
const mimcsponge = require("./mimcsponge");
exports.prv2pub= prv2pub;
exports.sign = sign;
exports.signMiMC = signMiMC;
exports.signMiMCSponge = signMiMCSponge;
exports.verify = verify;
exports.verifyMiMC = verifyMiMC;
exports.verifyMiMCSponge = verifyMiMCSponge;
exports.packSignature = packSignature;
exports.unpackSignature = unpackSignature;
exports.pruneBuffer = pruneBuffer;
@ -69,6 +72,25 @@ function signMiMC(prv, msg) {
};
}
function signMiMCSponge(prv, msg) {
const h1 = createBlakeHash("blake512").update(prv).digest();
const sBuff = pruneBuffer(h1.slice(0,32));
const s = bigInt.leBuff2int(sBuff);
const A = babyJub.mulPointEscalar(babyJub.Base8, s.shr(3));
const msgBuff = bigInt.leInt2Buff(msg, 32);
const rBuff = createBlakeHash("blake512").update(Buffer.concat([h1.slice(32,64), msgBuff])).digest();
let r = bigInt.leBuff2int(rBuff);
r = r.mod(babyJub.subOrder);
const R8 = babyJub.mulPointEscalar(babyJub.Base8, r);
const hm = mimcsponge.multiHash([R8[0], R8[1], A[0], A[1], msg]);
const S = r.add(hm.mul(s)).mod(babyJub.subOrder);
return {
R8: R8,
S: S
};
}
function verify(msg, sig, A) {
// Check parameters
if (typeof sig != "object") return false;
@ -116,6 +138,28 @@ function verifyMiMC(msg, sig, A) {
return true;
}
function verifyMiMCSponge(msg, sig, A) {
// Check parameters
if (typeof sig != "object") return false;
if (!Array.isArray(sig.R8)) return false;
if (sig.R8.length!= 2) return false;
if (!babyJub.inCurve(sig.R8)) return false;
if (!Array.isArray(A)) return false;
if (A.length!= 2) return false;
if (!babyJub.inCurve(A)) return false;
if (sig.S>= babyJub.subOrder) return false;
const hm = mimcsponge.multiHash([sig.R8[0], sig.R8[1], A[0], A[1], msg]);
const Pleft = babyJub.mulPointEscalar(babyJub.Base8, sig.S);
let Pright = babyJub.mulPointEscalar(A, hm.mul(bigInt("8")));
Pright = babyJub.addPoint(sig.R8, Pright);
if (!Pleft[0].equals(Pright[0])) return false;
if (!Pleft[1].equals(Pright[1])) return false;
return true;
}
function packSignature(sig) {
const R8p = babyJub.packPoint(sig.R8);
const Sp = bigInt.leInt2Buff(sig.S, 32);

+ 4
- 0
src/mimcsponge.js

@ -53,6 +53,10 @@ exports.multiHash = (arr, key, numOutputs) => {
if (typeof(numOutputs) === "undefined") {
numOutputs = 1;
}
if (typeof(key) === "undefined") {
key = F.zero;
}
let R = F.zero;
let C = F.zero;

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