Versie 0.2.0

client/nostr/nip44.js

@@ -0,0 +1,74 @@
+// Generated, do not edit. sha256:c9e44c618374bc6218029ec68095d9d8a62c6e5839ffe1dd3084b46600ccb118
+import {
+  secp256k1, sha256, chacha20, hkdfExtract, hkdfExpand, hmac, base64,
+  hexToBytes, utf8ToBytes, concatBytes,
+} from '../vendor/crypto/noble-scure.js';
+
+const VERSION = 2;
+const SALT = utf8ToBytes('nip44-v2');
+const MIN = 1;
+const MAX = 65535;
+
+const asBytes = (x) => (typeof x === 'string' ? hexToBytes(x) : x);
+
+export function conversationKey(secret, pubkey) {
+  const shared = secp256k1.getSharedSecret(asBytes(secret), concatBytes(Uint8Array.of(2), asBytes(pubkey)));
+  return hkdfExtract(sha256, shared.subarray(1, 33), SALT);
+}
+
+export function messageKeys(convKey, nonce) {
+  const keys = hkdfExpand(sha256, asBytes(convKey), asBytes(nonce), 76);
+  return { chachaKey: keys.subarray(0, 32), chachaNonce: keys.subarray(32, 44), hmacKey: keys.subarray(44, 76) };
+}
+
+export function paddedLength(len) {
+  if (len <= 32) return 32;
+  const next = 1 << (Math.floor(Math.log2(len - 1)) + 1);
+  const chunk = next <= 256 ? 32 : next / 8;
+  return chunk * (Math.floor((len - 1) / chunk) + 1);
+}
+
+function pad(text) {
+  const bytes = utf8ToBytes(text);
+  if (bytes.length < MIN || bytes.length > MAX) throw new Error(`A NIP-44 message is ${MIN} to ${MAX} bytes.`);
+  const out = new Uint8Array(2 + paddedLength(bytes.length));
+  out[0] = bytes.length >> 8;
+  out[1] = bytes.length & 0xff;
+  out.set(bytes, 2);
+  return out;
+}
+
+function unpad(padded) {
+  const len = (padded[0] << 8) | padded[1];
+  if (len < MIN || padded.length !== 2 + paddedLength(len)) throw new Error('Invalid padding.');
+  return new TextDecoder('utf-8', { fatal: true }).decode(padded.subarray(2, 2 + len));
+}
+
+function sameBytes(a, b) {
+  if (a.length !== b.length) return false;
+  let d = 0;
+  for (let i = 0; i < a.length; i++) d |= a[i] ^ b[i];
+  return d === 0;
+}
+
+export function encrypt(text, convKey, nonce = crypto.getRandomValues(new Uint8Array(32))) {
+  const n = asBytes(nonce);
+  const { chachaKey, chachaNonce, hmacKey } = messageKeys(convKey, n);
+  const ciphertext = chacha20(chachaKey, chachaNonce, pad(text));
+  const mac = hmac(sha256, hmacKey, concatBytes(n, ciphertext));
+  return base64.encode(concatBytes(Uint8Array.of(VERSION), n, ciphertext, mac));
+}
+
+export function decrypt(payload, convKey) {
+  const p = String(payload ?? '');
+  if (!p || p[0] === '#') throw new Error('Unknown NIP-44 version.');
+  if (p.length < 132 || p.length > 87472) throw new Error('Invalid NIP-44 payload length.');
+  const data = base64.decode(p);
+  if (data[0] !== VERSION) throw new Error(`Unknown NIP-44 version ${data[0]}.`);
+  const nonce = data.subarray(1, 33);
+  const ciphertext = data.subarray(33, data.length - 32);
+  const mac = data.subarray(data.length - 32);
+  const { chachaKey, chachaNonce, hmacKey } = messageKeys(convKey, nonce);
+  if (!sameBytes(mac, hmac(sha256, hmacKey, concatBytes(nonce, ciphertext)))) throw new Error('Invalid MAC.');
+  return unpad(chacha20(chachaKey, chachaNonce, ciphertext));
+}