/**
 * RSA Encryption Utilities
 */
/**
 * Encrypt data using RSA public key in chunks
 *
 * The merchant_auth field requires RSA encryption of a JSON object.
 * Due to RSA key size limitations, data is encrypted in chunks.
 *
 * @param data - Data to encrypt (will be JSON stringified)
 * @param publicKey - RSA public key (PEM format)
 * @param maxChunkSize - Maximum chunk size (default: 117 for 1024-bit keys)
 * @returns Base64 encoded encrypted data
 * @throws {Error} If encryption fails
 *
 * @example
 * const data = { mc_id: 'ec000002', tran_id: '123', refund_amount: 10.00 };
 * const encrypted = encryptRSA(data, rsaPublicKey);
 */
export declare function encryptRSA(data: any, publicKey: string, maxChunkSize?: number): string;
/**
 * Decrypt RSA encrypted data (for testing/verification)
 *
 * @param encryptedData - Base64 encoded encrypted data
 * @param privateKey - RSA private key (PEM format)
 * @param chunkSize - Encrypted chunk size (default: 128 for 1024-bit keys)
 * @returns Decrypted string
 * @throws {Error} If decryption fails
 */
export declare function decryptRSA(encryptedData: string, privateKey: string, chunkSize?: number): string;