Add generate randomness

contribution/contribution.js

@@ -1,4 +1,21 @@
 const bls = require('@noble/curves/bls12-381');
+const crypto = require('crypto');
+const os = require('os');
+
+function generateRandom(){
+    const [seconds, nanoseconds] = process.hrtime();
+    const seed = os.hostname() + os.freemem() + seconds + nanoseconds;
+
+    const hash = crypto.createHash('keccak256');
+    hash.update(seed);
+    const seedHash = hash.digest();
+    const seedInt = seedHash.readInt32LE();
+
+    randomBytes = crypto.randomBytes(32);
+    const randomInt = (parseInt(randomBytes.toString('hex'), 16) + seedInt);
+    const randomBigInt = BigInt(randomInt);
+    return randomBigInt % Fr.ORDER;
+}
 
 // TODO: Confirm by initialContribution.json
 // TODO: Support multi-thread?
@@ -18,12 +35,11 @@ function contribute(contributions, rand) {
         const g1Powers = contributions[i].powersOfTau.G1Powers;
         const g2Powers = contributions[i].powersOfTau.G2Powers;
 
-        var xi = 1n;
         for(var j = 0; j < contributions[i].numG1Powers; j++) {
             const g1Affine = g1Powers[j];
             const g1PrjPoint = G1Point.fromAffine(g1Affine);
 
-            const g1NewPrjPoint = g1PrjPoint.multiply(xi);
+            const g1NewPrjPoint = g1PrjPoint.multiply(rand[i]);
             const g1NewAffine = g1NewPrjPoint.toAffine();
 
             contributions[i].powersOfTau.G1Powers[j] = g1NewAffine;
@@ -32,7 +48,7 @@ function contribute(contributions, rand) {
                 const g2Affine = g2Powers[j];
                 const g2PrjPoint = G2Point.fromAffine(g2Affine);
 
-                const g2NewPrjPoint = g2PrjPoint.multiply(xi);
+                const g2NewPrjPoint = g2PrjPoint.multiply(rand[i]);
                 const g2NewAffine = g2NewPrjPoint.toAffine();
 
                 contributions[i].powersOfTau.G2Powers[j] = g2NewAffine;
@@ -62,7 +78,7 @@ function updateWitness(contributions, rand) {
         console.log(potPubkeyAffine);
 
         const potPubkeyPrj = G2Point.fromAffine(potPubkeyAffine);
-        const newPubkeyPrj = potPubkeyPrj.multiply(rand)
+        const newPubkeyPrj = potPubkeyPrj.multiply(rand[i])
 
         const newPotPubkey = util.bytesToHex(G2.toBytes(G2Point, newPubkeyPrj, true));
         console.log('New PotPubkey', newPotPubkey);
@@ -76,4 +92,5 @@ function updateWitness(contributions, rand) {
 module.exports = {
     contribute: contribute,
     updateWitness: updateWitness,
+    generateRandom: generateRandom,
 };

index.js

@@ -62,13 +62,18 @@ program
         console.log('Decoding...');
         contributions = conversion.decode(resp.contributions);
 
-        const randValue = Math.floor(Math.random() * 100000); // TODO:
+        var rand = [];
+        for (var i =0; i < contributions.length; i++){
+            rand[i] = contribute.generateRandom();
+        }
 
         console.log('Update Power of Tau...');
-        var newContributions = contribute.contribute(contributions, BigInt(randValue));
+        var newContributions = contribute.contribute(contributions, rand);
 
         console.log('Update Witnesses...');
-        newContributions = contribute.updateWitness(newContributions, BigInt(randValue));
+        newContributions = contribute.updateWitness(newContributions, rand);
+
+        rand.length = 0;
 
         console.log('Encoding...');
         newContributions = conversion.encode(newContributions);