C++

RSA Encrypt and Decrypt Strings

See more RSA Examples

_LANGUAGE_ sample code to RSA public-key encrypt and decrypt strings using public and private keys. C++

#include <CkRsa.h>
#include <CkPrivateKey.h>
#include <CkPublicKey.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  This example assumes the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    CkRsa rsa;

    //  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 2048-bit key.  Chilkat RSA supports
    //  key sizes ranging from 512 bits to 4096 bits.
    CkPrivateKey privKey;
    success = rsa.GenKey(2048,privKey);
    if (success == false) {
        std::cout << rsa.lastErrorText() << "\r\n";
        return;
    }

    CkPublicKey pubKey;
    privKey.ToPublicKey(pubKey);

    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.
    success = rsaEncryptor.UsePublicKey(pubKey);

    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.UsePrivateKey(privKey);

    usePrivateKey = true;
    const char *decryptedStr = rsaDecryptor.decryptStringENC(encryptedStr,usePrivateKey);

    std::cout << decryptedStr << "\r\n";
    }