Fixed stuff

static/js/modules/crypto/paillier.js

@@ -1,24 +1,45 @@
-import { cryptoRandom, generate_prime } from "./random_primes.js";
+import { cryptoRandom, generate_prime, KEY_SIZE } from "./random_primes.js";
 import { gcd, mod_exp } from "./math.js";
 
+const PAILLIER = 0;
+const JURIK = 1;
+
 class Ciphertext {
     constructor(key, plainText, r) {
         if (r === undefined) {
-            r = cryptoRandom(2048);
+            // Use the optimised form using Jacobi classes
+            r = cryptoRandom();
+
+            // Compute g^m by binomial theorem.
+            let gm = (1n + key.n * plainText) % key.n2;
+
+            // Compute g^m h^r.
+            this.cipherText = (gm * mod_exp(key.hn, r, key.n2)) % key.n2;
+
+            // Force into range.
+            while (this.cipherText < 0n) {
+                this.cipherText += key.n2;
+            }
+
+            this.mode = JURIK;
+            this.r = mod_exp(key.h, r, key.n);
+        } else {
+            // Use the standard form
+            // Compute g^m by binomial theorem.
+            let gm = (1n + key.n * plainText) % key.n2;
+
+            // Compute g^m r^n.
+            this.cipherText = (gm * mod_exp(r, key.n, key.n2)) % key.n2;
+
+            // Force into range.
+            while (this.cipherText < 0n) {
+                this.cipherText += key.n2;
+            }
+
+            this.mode = PAILLIER;
+            this.r = r;
         }
 
-        // Compute g^m by binomial theorem.
-        let gm = (1n + key.n * plainText) % key.n2;
-
-        // Compute g^m h^r.
-        this.cipherText = (gm * mod_exp(key.hn, r, key.n2)) % key.n2;
-
-        // Force into range.
-        while (this.cipherText < 0n) {
-            this.cipherText += key.n2;
-        }
-
-        this.r = r;
         this.pubKey = key;
         this.plainText = plainText;
 
@@ -46,9 +67,9 @@ class Ciphertext {
 
     // Construct a non-interactive proof
     proveNI() {
-        let rp = cryptoRandom(4096);
+        let rp = cryptoRandom(KEY_SIZE * 2);
         while (rp >= this.pubKey.n) {
-            rp = cryptoRandom(4096);
+            rp = cryptoRandom(KEY_SIZE * 2);
         }
 
         let a = mod_exp(rp, this.pubKey.n, this.pubKey.n2);
@@ -92,9 +113,9 @@ class ValueProofSessionProver {
     constructor(cipherText) {
         this.cipherText = cipherText;
 
-        this.rp = cryptoRandom(4096);
+        this.rp = cryptoRandom(KEY_SIZE * 2);
         while (this.rp >= this.cipherText.pubKey.n) {
-            this.rp = cryptoRandom(4096);
+            this.rp = cryptoRandom(KEY_SIZE * 2);
         }
     }
 
@@ -168,7 +189,7 @@ class ValueProofSessionVerifier {
 
         if (challenge === undefined) {
             // Shift the challenge down by 1 to ensure it is smaller than either prime factor.
-            this.challenge = cryptoRandom(2048) << 1n;
+            this.challenge = cryptoRandom(KEY_SIZE) << 1n;
         } else {
             this.challenge = challenge;
         }
@@ -205,10 +226,9 @@ export class PaillierPubKey {
         this.n = n;
 
         if (h === undefined) {
-            let x = cryptoRandom(4096);
-
+            let x = cryptoRandom(KEY_SIZE * 2);
             while (x >= this.n) {
-                x = cryptoRandom(4096);
+                x = cryptoRandom(KEY_SIZE * 2);
             }
 
             this.h = ((-1n * x ** 2n) % this.n) + this.n;

static/js/modules/crypto/random_primes.js

@@ -1,8 +1,10 @@
 import { mod_exp } from "./math.js";
 
+export const KEY_SIZE = 512;
+
 export function cryptoRandom(bits) {
     if (bits === undefined) {
-        bits = 2048;
+        bits = KEY_SIZE;
     }
     let length = bits / 64;
 
@@ -29,7 +31,7 @@ function generate_bigint() {
     intRepr >>= 1n;
 
     // Add 2^2047 to force into range from below
-    intRepr += 2n ** 2047n;
+    intRepr += 2n ** BigInt(KEY_SIZE - 1);
 
     return intRepr;
 }

static/js/modules/interface/proofs.js

@@ -1,4 +1,8 @@
-// Fisher-Yates shuffle
+/**
+ * CSPRNG Fisher-Yates shuffle.
+ *
+ * Only works on lists up to 255 elements.
+ */
 function cryptoShuffle(l) {
     for (let i = l.length - 1; i > 0; i--) {
         let value = new Uint8Array([0]);