generating WG keypair in browser using Web Crypto API (#422)

frontend/src/views/KeyGeneraterView.vue

@@ -6,188 +6,94 @@ const privateKey = ref("")
 const publicKey = ref("")
 const presharedKey = ref("")
 
-// region wireguard.js
+/**
-// taken from: https://github.com/WireGuard/wireguard-tools/blob/master/contrib/keygen-html/wireguard.js
+ * Generate an X25519 keypair using the Web Crypto API and return Base64-encoded strings.
+ * @async
+ * @function generateKeypair
+ * @returns {Promise<{ publicKey: string, privateKey: string }>} Resolves with an object containing
+ *   - publicKey: the Base64-encoded public key
+ *   - privateKey: the Base64-encoded private key
+ */
+async function generateKeypair() {
+  // 1. Generate an X25519 key pair
+  const keyPair = await crypto.subtle.generateKey(
+      { name: 'X25519', namedCurve: 'X25519' },
+      true,                 // extractable
+      ['deriveBits']        // allowed usage for ECDH
+  );
 
-function gf(init) {
+  // 2. Export keys as JWK to access raw key material
-  let r = new Float64Array(16);
+  const pubJwk  = await crypto.subtle.exportKey('jwk', keyPair.publicKey);
-  if (init) {
+  const privJwk = await crypto.subtle.exportKey('jwk', keyPair.privateKey);
-    for (let i = 0; i < init.length; ++i)
+
-      r[i] = init[i];
+  // 3. Convert Base64URL to standard Base64 with padding
-  }
+  return {
-  return r;
+    publicKey:  b64urlToB64(pubJwk.x),
-}
+    privateKey: b64urlToB64(privJwk.d)
-
+  };
-function pack(o, n) {
-  let b, m = gf(), t = gf();
-  for (let i = 0; i < 16; ++i)
-    t[i] = n[i];
-  carry(t);
-  carry(t);
-  carry(t);
-  for (let j = 0; j < 2; ++j) {
-    m[0] = t[0] - 0xffed;
-    for (let i = 1; i < 15; ++i) {
-      m[i] = t[i] - 0xffff - ((m[i - 1] >> 16) & 1);
-      m[i - 1] &= 0xffff;
-    }
-    m[15] = t[15] - 0x7fff - ((m[14] >> 16) & 1);
-    b = (m[15] >> 16) & 1;
-    m[14] &= 0xffff;
-    cswap(t, m, 1 - b);
-  }
-  for (let i = 0; i < 16; ++i) {
-    o[2 * i] = t[i] & 0xff;
-    o[2 * i + 1] = t[i] >> 8;
-  }
-}
-
-function carry(o) {
-  for (let i = 0; i < 16; ++i) {
-    o[(i + 1) % 16] += (i < 15 ? 1 : 38) * Math.floor(o[i] / 65536);
-    o[i] &= 0xffff;
-  }
-}
-
-function cswap(p, q, b) {
-  let t, c = ~(b - 1);
-  for (let i = 0; i < 16; ++i) {
-    t = c & (p[i] ^ q[i]);
-    p[i] ^= t;
-    q[i] ^= t;
-  }
-}
-
-function add(o, a, b) {
-  for (let i = 0; i < 16; ++i)
-    o[i] = (a[i] + b[i]) | 0;
-}
-
-function subtract(o, a, b) {
-  for (let i = 0; i < 16; ++i)
-    o[i] = (a[i] - b[i]) | 0;
-}
-
-function multmod(o, a, b) {
-  let t = new Float64Array(31);
-  for (let i = 0; i < 16; ++i) {
-    for (let j = 0; j < 16; ++j)
-      t[i + j] += a[i] * b[j];
-  }
-  for (let i = 0; i < 15; ++i)
-    t[i] += 38 * t[i + 16];
-  for (let i = 0; i < 16; ++i)
-    o[i] = t[i];
-  carry(o);
-  carry(o);
-}
-
-function invert(o, i) {
-  let c = gf();
-  for (let a = 0; a < 16; ++a)
-    c[a] = i[a];
-  for (let a = 253; a >= 0; --a) {
-    multmod(c, c, c);
-    if (a !== 2 && a !== 4)
-      multmod(c, c, i);
-  }
-  for (let a = 0; a < 16; ++a)
-    o[a] = c[a];
-}
-
-function clamp(z) {
-  z[31] = (z[31] & 127) | 64;
-  z[0] &= 248;
-}
-
-function generatePublicKey(privateKey) {
-  let r, z = new Uint8Array(32);
-  let a = gf([1]),
-      b = gf([9]),
-      c = gf(),
-      d = gf([1]),
-      e = gf(),
-      f = gf(),
-      _121665 = gf([0xdb41, 1]),
-      _9 = gf([9]);
-  for (let i = 0; i < 32; ++i)
-    z[i] = privateKey[i];
-  clamp(z);
-  for (let i = 254; i >= 0; --i) {
-    r = (z[i >>> 3] >>> (i & 7)) & 1;
-    cswap(a, b, r);
-    cswap(c, d, r);
-    add(e, a, c);
-    subtract(a, a, c);
-    add(c, b, d);
-    subtract(b, b, d);
-    multmod(d, e, e);
-    multmod(f, a, a);
-    multmod(a, c, a);
-    multmod(c, b, e);
-    add(e, a, c);
-    subtract(a, a, c);
-    multmod(b, a, a);
-    subtract(c, d, f);
-    multmod(a, c, _121665);
-    add(a, a, d);
-    multmod(c, c, a);
-    multmod(a, d, f);
-    multmod(d, b, _9);
-    multmod(b, e, e);
-    cswap(a, b, r);
-    cswap(c, d, r);
-  }
-  invert(c, c);
-  multmod(a, a, c);
-  pack(z, a);
-  return z;
 }
 
+/**
+ * Generate a 32-byte pre-shared key using crypto.getRandomValues.
+ * @function generatePresharedKey
+ * @returns {Uint8Array} A Uint8Array of length 32 with random bytes.
+ */
 function generatePresharedKey() {
   let privateKey = new Uint8Array(32);
   window.crypto.getRandomValues(privateKey);
   return privateKey;
 }
 
-function generatePrivateKey() {
+/**
-  let privateKey = generatePresharedKey();
+ * Convert a Base64URL-encoded string to standard Base64 with padding.
-  clamp(privateKey);
+ * @function b64urlToB64
-  return privateKey;
+ * @param {string} input - The Base64URL string.
+ * @returns {string} The padded, standard Base64 string.
+ */
+function b64urlToB64(input) {
+  let b64 = input.replace(/-/g, '+').replace(/_/g, '/');
+  while (b64.length % 4) {
+    b64 += '=';
+  }
+  return b64;
 }
 
-function encodeBase64(dest, src) {
+/**
-  let input = Uint8Array.from([(src[0] >> 2) & 63, ((src[0] << 4) | (src[1] >> 4)) & 63, ((src[1] << 2) | (src[2] >> 6)) & 63, src[2] & 63]);
+ * Convert an ArrayBuffer or TypedArray buffer to a Base64-encoded string.
-  for (let i = 0; i < 4; ++i)
+ * @function arrayBufferToBase64
-    dest[i] = input[i] + 65 +
+ * @param {ArrayBuffer|Uint8Array} buffer - The buffer to convert.
-        (((25 - input[i]) >> 8) & 6) -
+ * @returns {string} Base64-encoded representation of the buffer.
-        (((51 - input[i]) >> 8) & 75) -
+ */
-        (((61 - input[i]) >> 8) & 15) +
+function arrayBufferToBase64(buffer) {
-        (((62 - input[i]) >> 8) & 3);
+  const bytes = new Uint8Array(buffer);
+  let binary = '';
+  for (let i = 0; i < bytes.byteLength; ++i) {
+    binary += String.fromCharCode(bytes[i]);
+  }
+  // Window.btoa handles binary → Base64
+  return btoa(binary);
 }
 
-function keyToBase64(key) {
+/**
-  let i, base64 = new Uint8Array(44);
+ * Generate a new keypair and update the corresponding Vue refs.
-  for (i = 0; i < 32 / 3; ++i)
+ * @async
-    encodeBase64(base64.subarray(i * 4), key.subarray(i * 3));
+ * @function generateNewKeyPair
-  encodeBase64(base64.subarray(i * 4), Uint8Array.from([key[i * 3 + 0], key[i * 3 + 1], 0]));
+ * @returns {Promise<void>}
-  base64[43] = 61;
+ */
-  return String.fromCharCode.apply(null, base64);
+async function generateNewKeyPair() {
-}
+  const keypair = await generateKeypair();
-
+
-// endregion wireguard.js
+  privateKey.value = keypair.privateKey;
-
+  publicKey.value = keypair.publicKey;
-function generateNewKeyPair() {
-  const priv = generatePrivateKey();
-  const pub = generatePublicKey(priv);
-  
-  privateKey.value = keyToBase64(priv);
-  publicKey.value = keyToBase64(pub);
 }
 
+/**
+ * Generate a new pre-shared key and update the Vue ref.
+ * @function generateNewPresharedKey
+ */
 function generateNewPresharedKey() {
-  const psk = generatePresharedKey();
+  const rawPsk = generatePresharedKey();
-  presharedKey.value = keyToBase64(psk);
+  presharedKey.value = arrayBufferToBase64(rawPsk);
 }
 
 </script>