/** Generate a random token as a hex string. */
declare function generateToken(): string;
/** SHA-256 hash a string, returning hex. */
declare function hashToken(token: string): string;
/** Derive an AES-256 key from a token and salt using PBKDF2. */
declare function deriveKey(token: string, salt: Buffer): Buffer;
/** Encrypt plaintext using AES-256-GCM. Returns { salt, iv, authTag, ciphertext } as hex. */
declare function encrypt(plaintext: string, token: string): {
    salt: string;
    iv: string;
    authTag: string;
    ciphertext: string;
};
/** Decrypt ciphertext using AES-256-GCM. */
declare function decrypt(data: {
    salt: string;
    iv: string;
    authTag: string;
    ciphertext: string;
}, token: string): string;
export { generateToken, hashToken, deriveKey, encrypt, decrypt };