feat: add secret derivation for KeePass key files

src/kdbx/crypto.ts

@@ -13,3 +13,20 @@ export function deriveKey(password: string, salt: Uint8Array, rounds: number, le
 
 	return new Uint8Array(pbkdf2Sync(password, Buffer.from(salt), rounds, length, "sha256"));
 }
+
+export function normalizeKeyFileBytes(bytes: Uint8Array): Uint8Array {
+	return sha256(bytes);
+}
+
+export function combineSecrets(password: string, keyFileBytes?: Uint8Array): Uint8Array {
+	const passwordHash = sha256(password);
+	if (!keyFileBytes) return passwordHash;
+	return sha256(Buffer.concat([Buffer.from(passwordHash), Buffer.from(normalizeKeyFileBytes(keyFileBytes))]));
+}
+
+export function deriveMasterKey(secret: Uint8Array, salt: Uint8Array, rounds: number): Uint8Array {
+	if (secret.length === 0) {
+		throw new Error("Missing secret for key derivation");
+	}
+	return new Uint8Array(pbkdf2Sync(Buffer.from(secret), Buffer.from(salt), rounds, 32, "sha256"));
+}