import type { KeychainManager } from "../types.js";
export declare class FallbackKeychainManager implements KeychainManager {
    private keysDir;
    constructor(keysDir?: string);
    private ensureKeysDir;
    private getKeyPath;
    isAvailable(): boolean;
    storeMasterKey(keyId: string, keyMaterial: Uint8Array): Promise<void>;
    retrieveMasterKey(keyId: string): Promise<Uint8Array | null>;
    deleteMasterKey(keyId: string): Promise<void>;
    storeMasterKeySync(keyId: string, keyMaterial: Uint8Array): void;
    retrieveMasterKeySync(keyId: string): Uint8Array | null;
    deleteMasterKeySync(keyId: string): void;
}