1const createBlakeHash = require("blake-hash");
  2const bigInt = require("snarkjs").bigInt;
  3const babyJub = require("./babyjub");
  4const pedersenHash = require("./pedersenHash").hash;
  5const mimc7 = require("./mimc7");
  6const mimcsponge = require("./mimcsponge");
  7
  8exports.prv2pub= prv2pub;
  9exports.sign = sign;
 10exports.signMiMC = signMiMC;
 11exports.signMiMCSponge = signMiMCSponge;
 12exports.verify = verify;
 13exports.verifyMiMC = verifyMiMC;
 14exports.verifyMiMCSponge = verifyMiMCSponge;
 15exports.packSignature = packSignature;
 16exports.unpackSignature = unpackSignature;
 17exports.pruneBuffer = pruneBuffer;
 18
 19
 20function pruneBuffer(_buff) {
 21    const buff = Buffer.from(_buff);
 22    buff[0] = buff[0] & 0xF8;
 23    buff[31] = buff[31] & 0x7F;
 24    buff[31] = buff[31] | 0x40;
 25    return buff;
 26}
 27
 28function prv2pub(prv) {
 29    const sBuff = pruneBuffer(createBlakeHash("blake512").update(prv).digest().slice(0,32));
 30    let s = bigInt.leBuff2int(sBuff);
 31    const A = babyJub.mulPointEscalar(babyJub.Base8, s.shr(3));
 32    return A;
 33}
 34
 35function sign(prv, msg) {
 36    const h1 = createBlakeHash("blake512").update(prv).digest();
 37    const sBuff = pruneBuffer(h1.slice(0,32));
 38    const s = bigInt.leBuff2int(sBuff);
 39    const A = babyJub.mulPointEscalar(babyJub.Base8, s.shr(3));
 40
 41    const rBuff = createBlakeHash("blake512").update(Buffer.concat([h1.slice(32,64), msg])).digest();
 42    let r = bigInt.leBuff2int(rBuff);
 43    r = r.mod(babyJub.subOrder);
 44    const R8 = babyJub.mulPointEscalar(babyJub.Base8, r);
 45    const R8p = babyJub.packPoint(R8);
 46    const Ap = babyJub.packPoint(A);
 47    const hmBuff = pedersenHash(Buffer.concat([R8p, Ap, msg]));
 48    const hm = bigInt.leBuff2int(hmBuff);
 49    const S = r.add(hm.mul(s)).mod(babyJub.subOrder);
 50    return {
 51        R8: R8,
 52        S: S
 53    };
 54}
 55
 56function signMiMC(prv, msg) {
 57    const h1 = createBlakeHash("blake512").update(prv).digest();
 58    const sBuff = pruneBuffer(h1.slice(0,32));
 59    const s = bigInt.leBuff2int(sBuff);
 60    const A = babyJub.mulPointEscalar(babyJub.Base8, s.shr(3));
 61
 62    const msgBuff = bigInt.leInt2Buff(msg, 32);
 63    const rBuff = createBlakeHash("blake512").update(Buffer.concat([h1.slice(32,64), msgBuff])).digest();
 64    let r = bigInt.leBuff2int(rBuff);
 65    r = r.mod(babyJub.subOrder);
 66    const R8 = babyJub.mulPointEscalar(babyJub.Base8, r);
 67    const hm = mimc7.multiHash([R8[0], R8[1], A[0], A[1], msg]);
 68    const S = r.add(hm.mul(s)).mod(babyJub.subOrder);
 69    return {
 70        R8: R8,
 71        S: S
 72    };
 73}
 74
 75function signMiMCSponge(prv, msg) {
 76    const h1 = createBlakeHash("blake512").update(prv).digest();
 77    const sBuff = pruneBuffer(h1.slice(0,32));
 78    const s = bigInt.leBuff2int(sBuff);
 79    const A = babyJub.mulPointEscalar(babyJub.Base8, s.shr(3));
 80
 81    const msgBuff = bigInt.leInt2Buff(msg, 32);
 82    const rBuff = createBlakeHash("blake512").update(Buffer.concat([h1.slice(32,64), msgBuff])).digest();
 83    let r = bigInt.leBuff2int(rBuff);
 84    r = r.mod(babyJub.subOrder);
 85    const R8 = babyJub.mulPointEscalar(babyJub.Base8, r);
 86    const hm = mimcsponge.multiHash([R8[0], R8[1], A[0], A[1], msg]);
 87    const S = r.add(hm.mul(s)).mod(babyJub.subOrder);
 88    return {
 89        R8: R8,
 90        S: S
 91    };
 92}
 93
 94function verify(msg, sig, A) {
 95    // Check parameters
 96    if (typeof sig != "object") return false;
 97    if (!Array.isArray(sig.R8)) return false;
 98    if (sig.R8.length!= 2) return false;
 99    if (!babyJub.inCurve(sig.R8)) return false;
100    if (!Array.isArray(A)) return false;
101    if (A.length!= 2) return false;
102    if (!babyJub.inCurve(A)) return false;
103    if (sig.S>= babyJub.subOrder) return false;
104
105    const R8p = babyJub.packPoint(sig.R8);
106    const Ap = babyJub.packPoint(A);
107    const hmBuff = pedersenHash(Buffer.concat([R8p, Ap, msg]));
108    const hm = bigInt.leBuff2int(hmBuff);
109
110    const Pleft = babyJub.mulPointEscalar(babyJub.Base8, sig.S);
111    let Pright = babyJub.mulPointEscalar(A, hm.mul(bigInt("8")));
112    Pright = babyJub.addPoint(sig.R8, Pright);
113
114    if (!Pleft[0].equals(Pright[0])) return false;
115    if (!Pleft[1].equals(Pright[1])) return false;
116    return true;
117}
118
119function verifyMiMC(msg, sig, A) {
120    // Check parameters
121    if (typeof sig != "object") return false;
122    if (!Array.isArray(sig.R8)) return false;
123    if (sig.R8.length!= 2) return false;
124    if (!babyJub.inCurve(sig.R8)) return false;
125    if (!Array.isArray(A)) return false;
126    if (A.length!= 2) return false;
127    if (!babyJub.inCurve(A)) return false;
128    if (sig.S>= babyJub.subOrder) return false;
129
130    const hm = mimc7.multiHash([sig.R8[0], sig.R8[1], A[0], A[1], msg]);
131
132    const Pleft = babyJub.mulPointEscalar(babyJub.Base8, sig.S);
133    let Pright = babyJub.mulPointEscalar(A, hm.mul(bigInt("8")));
134    Pright = babyJub.addPoint(sig.R8, Pright);
135
136    if (!Pleft[0].equals(Pright[0])) return false;
137    if (!Pleft[1].equals(Pright[1])) return false;
138    return true;
139}
140
141function verifyMiMCSponge(msg, sig, A) {
142    // Check parameters
143    if (typeof sig != "object") return false;
144    if (!Array.isArray(sig.R8)) return false;
145    if (sig.R8.length!= 2) return false;
146    if (!babyJub.inCurve(sig.R8)) return false;
147    if (!Array.isArray(A)) return false;
148    if (A.length!= 2) return false;
149    if (!babyJub.inCurve(A)) return false;
150    if (sig.S>= babyJub.subOrder) return false;
151
152    const hm = mimcsponge.multiHash([sig.R8[0], sig.R8[1], A[0], A[1], msg]);
153
154    const Pleft = babyJub.mulPointEscalar(babyJub.Base8, sig.S);
155    let Pright = babyJub.mulPointEscalar(A, hm.mul(bigInt("8")));
156    Pright = babyJub.addPoint(sig.R8, Pright);
157
158    if (!Pleft[0].equals(Pright[0])) return false;
159    if (!Pleft[1].equals(Pright[1])) return false;
160    return true;
161}
162
163function packSignature(sig) {
164    const R8p = babyJub.packPoint(sig.R8);
165    const Sp = bigInt.leInt2Buff(sig.S, 32);
166    return Buffer.concat([R8p, Sp]);
167}
168
169function unpackSignature(sigBuff) {
170    return {
171        R8: babyJub.unpackPoint(sigBuff.slice(0,32)),
172        S: bigInt.leBuff2int(sigBuff.slice(32,64))
173    };
174}
175
176