85 lines
1.8 KiB
JavaScript
85 lines
1.8 KiB
JavaScript
const bn128 = require("snarkjs").bn128;
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const bigInt = require("snarkjs").bigInt;
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const createBlakeHash = require("blake-hash");
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const assert = require("assert");
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function getPoint(S) {
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const F = bn128.Fr;
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const h = createBlakeHash("blake256").update(S).digest();
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assert(h.length == 32);
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let sign = false;
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if (h[31] & 0x80) {
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h[31] = h[31] & 0x7F;
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sign = true;
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}
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let x = bigInt(0);
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for (let i=0; i<32; i++) {
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x = x.shl(8);
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x = x.add(bigInt(h[i]));
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}
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const a = bigInt("168700");
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const d = bigInt("168696");
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const x2 = F.square(x);
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let y = F.sqrt(F.div(
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F.sub(F.one, F.mul(a, x2)),
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F.sub(F.one, F.mul(d, x2))));
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if (y == null) return null;
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if (sign) y = F.neg(y);
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return [bn128.Fr.affine(x), bn128.Fr.affine(y)];
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}
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function generatePoint(S) {
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let p= null;
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let idx = 0;
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while (p==null) {
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let sidx = "" + idx;
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while (sidx.length<16) sidx = "0"+sidx;
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p = getPoint(S+"_"+sidx);
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idx++;
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}
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assert(inCurve(p));
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return p;
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}
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function inCurve(p) {
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const F = bn128.Fr;
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const a = bigInt("168700");
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const d = bigInt("168696");
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const x2 = F.square(p[0]);
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const y2 = F.square(p[1]);
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return F.equals(
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F.add(F.mul(a, x2), y2),
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F.add(F.one, F.mul(F.mul(x2, y2), d)));
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}
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const g = [
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bigInt("17777552123799933955779906779655732241715742912184938656739573121738514868268"),
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bigInt("2626589144620713026669568689430873010625803728049924121243784502389097019475")];
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if (!inCurve(g)) {
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throw new Error("Generator not In curve -> Some thing goes wrong...");
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}
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for (let i=0; i<25; i++) {
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let S = "" +i;
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while (S.length<16) S = "0"+S;
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const P = generatePoint("Iden3_PedersenGenerator_"+S);
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console.log(`[${P[0].toString()}, ${P[1].toString()}]`);
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}
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