/**
 * Key management service (KMS) driver.
 */
export interface KmsDriver {
    getKeyUrlPrefix(): string;
    newKmsClient(config: Map<string, string>, keyUrl: string): KmsClient;
}
/**
 * Key management service (KMS) client.
 */
export interface KmsClient {
    supported(keyUri: string): boolean;
    encrypt(plaintext: Buffer): Promise<Buffer>;
    decrypt(ciphertext: Buffer): Promise<Buffer>;
}
/**
 * Register a KMS driver.
 * @param kmsDriver - the KMS driver to register
 */
export declare function registerKmsDriver(kmsDriver: KmsDriver): void;
/**
 * Get the KMS driver for the given key URL.
 * @param keyUrl - the key URL
 */
export declare function getKmsDriver(keyUrl: string): KmsDriver;
/**
 * Register a KMS client.
 * @param kmsClient - the KMS client to register
 */
export declare function registerKmsClient(kmsClient: KmsClient): void;
/**
 * Get the KMS client for the given key URL.
 * @param keyUrl - the key URL
 */
export declare function getKmsClient(keyUrl: string): KmsClient | null;
/**
 * Clear the KMS clients.
 */
export declare function clearKmsClients(): void;