1const bn128 = require("snarkjs").bn128;
 2const bigInt = require("snarkjs").bigInt;
 3const createBlakeHash = require("blake-hash");
 4const assert = require("assert");
 5const babyJub = require("../src/babyjub");
 6
 7function getPoint(S) {
 8    const F = bn128.Fr;
 9    const h = createBlakeHash("blake256").update(S).digest();
10
11    assert(h.length == 32);
12
13    let sign = false;
14    if (h[31] & 0x80) {
15        h[31] = h[31] & 0x7F;
16        sign = true;
17    }
18
19    let y = bigInt(0);
20    for (let i=0; i<32; i++) {
21        y = y.shl(8);
22        y = y.add(bigInt(h[i]));
23    }
24
25    const a = bigInt("168700");
26    const d = bigInt("168696");
27
28    const y2 = F.square(y);
29
30    let x = F.sqrt(F.div(
31        F.sub(F.one, y2),
32        F.sub(a, F.mul(d, y2))));
33
34    if (x == null) return null;
35
36    if (sign) x = F.neg(x);
37
38    const p = [bn128.Fr.affine(x), bn128.Fr.affine(y)];
39
40    const p8 = babyJub.mulPointEscalar(p, 8);
41
42    return p8;
43}
44
45
46function generatePoint(S) {
47    let p= null;
48    let idx = 0;
49    while (p==null) {
50        let sidx = "" + idx;
51        while (sidx.length<16) sidx = "0"+sidx;
52        p = getPoint(S+"_"+sidx);
53        idx++;
54    }
55    assert(babyJub.inCurve(p), "Point not in curve");
56    return p;
57}
58
59
60
61
62
63const g = [
64    bigInt("17777552123799933955779906779655732241715742912184938656739573121738514868268"),
65    bigInt("2626589144620713026669568689430873010625803728049924121243784502389097019475")];
66
67// Sanity check
68if (!babyJub.inCurve(g)) {
69    throw new Error("Generator not In curve -> Some thing goes wrong...");
70}
71
72for (let i=0; i<25; i++) {
73    let S = "" +i;
74    while (S.length<16) S = "0"+S;
75    const P = generatePoint("Iden3_PedersenGenerator_"+S);
76    console.log(`[${P[0].toString()}, ${P[1].toString()}]`);
77}
78
79
80