C++ sample code to RSA public-key encrypt and decrypt strings using public and private keys.
Chilkat C/C++ Library Downloads
#include <CkRsa.h> void ChilkatSample(void) { CkRsa rsa; bool success = rsa.UnlockComponent("Anything for 30-day trial"); if (success != true) { std::cout << "RSA component unlock failed" << "\r\n"; return; } // This example also generates the public and private // keys to be used in the RSA encryption. // Normally, you would generate a key pair once, // and distribute the public key to your partner. // Anything encrypted with the public key can be // decrypted with the private key. The reverse is // also true: anything encrypted using the private // key can be decrypted using the public key. // Generate a 1024-bit key. Chilkat RSA supports // key sizes ranging from 512 bits to 4096 bits. success = rsa.GenerateKey(1024); if (success != true) { std::cout << rsa.lastErrorText() << "\r\n"; return; } // Keys are exported in XML format: const char *publicKey = rsa.exportPublicKey(); const char *privateKey = rsa.exportPrivateKey(); const char *plainText = "Encrypting and decrypting should be easy!"; // Start with a new RSA object to demonstrate that all we // need are the keys previously exported: CkRsa rsaEncryptor; // Encrypted output is always binary. In this case, we want // to encode the encrypted bytes in a printable string. // Our choices are "hex", "base64", "url", "quoted-printable". rsaEncryptor.put_EncodingMode("hex"); // We'll encrypt with the public key and decrypt with the private // key. It's also possible to do the reverse. success = rsaEncryptor.ImportPublicKey(publicKey); bool usePrivateKey = false; const char *encryptedStr = rsaEncryptor.encryptStringENC(plainText,usePrivateKey); std::cout << encryptedStr << "\r\n"; // Now decrypt: CkRsa rsaDecryptor; rsaDecryptor.put_EncodingMode("hex"); success = rsaDecryptor.ImportPrivateKey(privateKey); usePrivateKey = true; const char *decryptedStr = rsaDecryptor.decryptStringENC(encryptedStr,usePrivateKey); std::cout << decryptedStr << "\r\n"; }