/**
 * Encrypts a given string using AES encryption and a secret key from the environment.
 * A UUID is prepended to the data to ensure the encrypted token is unique.
 *
 * @param {string} token - The string to encrypt.
 * @returns {string} The encrypted token as a Base64 string.
 * @throws {Error} If the environment variable `SECRET_KEY` is not set.
 *
 * @example
 * const encryptedToken = encrypt("Hello, World!");
 * console.log(encryptedToken); // Example: U2FsdGVkX1...
 */
export declare function encryptToken(token: string): string;
/**
 * Decrypts a previously encrypted token and extracts the original data.
 * The function expects the encrypted token to contain a UUID and the original data.
 *
 * @param {string} token - The Base64-encoded encrypted token.
 * @returns {string} The original decrypted data string.
 * @throws {Error} If the environment variable `SECRET_KEY` is not set.
 * @throws {Error} If the decrypted token is invalid or improperly formatted.
 *
 * @example
 * const decryptedData = decrypt(encryptedToken);
 * console.log(decryptedData); // Output: "Hello, World!"
 */
export declare function decryptToken(ctx: Ctx, token: string): string;