(MFC) RSA Encrypt Randomly Generated AES Key

Demonstrates how to RSA encrypt a randomly generated AES key.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkPrng.h>
#include <CkBinData.h>
#include <CkCert.h>
#include <CkPublicKey.h>
#include <CkRsa.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    // First generate a 256-bit AES key (32 bytes).
    CkPrng prng;
    CkBinData bdAesKey;
    bool success = prng.GenRandomBd(32,bdAesKey);

    // Use a public key from a certificate for RSA encryption.
    CkCert cert;

    success = cert.LoadFromFile("qa_data/pem/mf_public_rsa.pem");
    if (success == false) {
        strOut.append(cert.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkPublicKey *pubKey = cert.ExportPublicKey();
    if (cert.get_LastMethodSuccess() != true) {
        strOut.append(cert.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkRsa rsa;
    success = rsa.ImportPublicKeyObj(*pubKey);
    if (success == false) {
        strOut.append(rsa.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    delete pubKey;

    // RSA encrypt our 32-byte AES key.
    // The contents of bdAesKey are replaced with result of the RSA encryption.
    success = rsa.EncryptBd(bdAesKey,false);
    if (success == false) {
        strOut.append(rsa.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Return the result as a base64 string
    const char *encryptedAesKey = bdAesKey.getEncoded("base64");

    strOut.append("encrypted AES key = ");
    strOut.append(encryptedAesKey);
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }