export interface EncryptedEnvelope {
    __encrypted: true;
    version: 1 | 2;
    keyVersion?: 2;
    iv: string;
    tag: string;
    ciphertext: string;
    salt?: string;
}
export declare function encrypt(plaintext: string, secret: string): EncryptedEnvelope;
export declare function decrypt(envelope: EncryptedEnvelope, secret: string): string;
export declare function isEncryptedEnvelope(value: unknown): value is EncryptedEnvelope;