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node_modules/matrix-js-sdk/lib/crypto-api/recovery-key.js

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+/*
+ * Copyright 2024 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import bs58 from "bs58";
+
+// picked arbitrarily but to try & avoid clashing with any bitcoin ones
+// (which are also base58 encoded, but bitcoin's involve a lot more hashing)
+const OLM_RECOVERY_KEY_PREFIX = [0x8b, 0x01];
+const KEY_SIZE = 32;
+
+/**
+ * Encode a recovery key using the Matrix {@link https://spec.matrix.org/v1.11/appendices/#cryptographic-key-representation | Cryptographic key representation}
+ * @param key
+ */
+export function encodeRecoveryKey(key) {
+  const buf = new Uint8Array(OLM_RECOVERY_KEY_PREFIX.length + key.length + 1);
+  buf.set(OLM_RECOVERY_KEY_PREFIX, 0);
+  buf.set(key, OLM_RECOVERY_KEY_PREFIX.length);
+  let parity = 0;
+  for (let i = 0; i < buf.length - 1; ++i) {
+    parity ^= buf[i];
+  }
+  buf[buf.length - 1] = parity;
+  const base58key = bs58.encode(buf);
+  return base58key.match(/.{1,4}/g)?.join(" ");
+}
+
+/**
+ * Decode a recovery key encoded with the Matrix {@link https://spec.matrix.org/v1.11/appendices/#cryptographic-key-representation | Cryptographic key representation} encoding.
+ * @param recoveryKey
+ */
+export function decodeRecoveryKey(recoveryKey) {
+  const result = bs58.decode(recoveryKey.replace(/ /g, ""));
+  let parity = 0;
+  for (const b of result) {
+    parity ^= b;
+  }
+  if (parity !== 0) {
+    throw new Error("Incorrect parity");
+  }
+  for (let i = 0; i < OLM_RECOVERY_KEY_PREFIX.length; ++i) {
+    if (result[i] !== OLM_RECOVERY_KEY_PREFIX[i]) {
+      throw new Error("Incorrect prefix");
+    }
+  }
+  if (result.length !== OLM_RECOVERY_KEY_PREFIX.length + KEY_SIZE + 1) {
+    throw new Error("Incorrect length");
+  }
+  return Uint8Array.from(result.slice(OLM_RECOVERY_KEY_PREFIX.length, OLM_RECOVERY_KEY_PREFIX.length + KEY_SIZE));
+}
+//# sourceMappingURL=recovery-key.js.map