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node_modules/matrix-js-sdk/lib/utils/internal/deriveKeys.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.
+ */
+
+// salt for HKDF, with 8 bytes of zeros
+const zeroSalt = new Uint8Array(8);
+
+/**
+ * Derive AES and HMAC keys from a master key.
+ *
+ * This is used for deriving secret storage keys: see https://spec.matrix.org/v1.11/client-server-api/#msecret_storagev1aes-hmac-sha2 (step 1).
+ *
+ * @param key
+ * @param name
+ */
+export async function deriveKeys(key, name) {
+  const hkdfkey = await globalThis.crypto.subtle.importKey("raw", key, {
+    name: "HKDF"
+  }, false, ["deriveBits"]);
+  const keybits = await globalThis.crypto.subtle.deriveBits({
+    name: "HKDF",
+    salt: zeroSalt,
+    // @ts-ignore: https://github.com/microsoft/TypeScript-DOM-lib-generator/pull/879
+    info: new TextEncoder().encode(name),
+    hash: "SHA-256"
+  }, hkdfkey, 512);
+  const aesKey = keybits.slice(0, 32);
+  const hmacKey = keybits.slice(32);
+  const aesProm = globalThis.crypto.subtle.importKey("raw", aesKey, {
+    name: "AES-CTR"
+  }, false, ["encrypt", "decrypt"]);
+  const hmacProm = globalThis.crypto.subtle.importKey("raw", hmacKey, {
+    name: "HMAC",
+    hash: {
+      name: "SHA-256"
+    }
+  }, false, ["sign", "verify"]);
+  return Promise.all([aesProm, hmacProm]);
+}
+//# sourceMappingURL=deriveKeys.js.map