(MFC) Generate an RSA Key and Get as Base64 DER

Demonstrates how to generate a 2048-bit RSA key and return the public and private parts as unencrypted Base64 encoded DER.

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

See Also: Using MFC CString in Chilkat

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

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkRsa rsa;

    // Generate a 2048-bit key.  Chilkat RSA supports
    bool success = rsa.GenerateKey(2048);
    if (success != true) {
        strOut.append(rsa.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Get the public part of the key.
    CkPublicKey *pubKey = rsa.ExportPublicKeyObj();

    // There are two possible formats for representing the RSA public key 
    // in ASN.1 (DER).  The possible formats are PKCS1 and PKCS8.
    // We can get either by setting bChoosePkcs1 to true or false.
    bool bChoosePkcs1 = true;
    const char *pubKeyBase64Der = pubKey->getEncoded(bChoosePkcs1,"base64");
    strOut.append("Public Key Base64 DER:");
    strOut.append("\r\n");
    strOut.append(pubKeyBase64Der);
    strOut.append("\r\n");

    delete pubKey;

    // Now get the private key as Base64 DER:
    // Get the private part of the key.
    // (Note: A public key is actually just a subset of the private key.  
    //  If you have the private key, you also have the public key.
    //  Thus Chilkat provides a method to get the public key from the private key.)
    CkPrivateKey *privKey = rsa.ExportPrivateKeyObj();

    // Again, we can get PKCS1 or PKCS8, but with different methods:
    const char *privKeyPkcs1 = privKey->getPkcs1ENC("base64");
    strOut.append("Private Key PKCS1 Base64 DER:");
    strOut.append("\r\n");
    strOut.append(privKeyPkcs1);
    strOut.append("\r\n");

    const char *privKeyPkcs8 = privKey->getPkcs8ENC("base64");
    strOut.append("Private Key PKCS8 Base64 DER:");
    strOut.append("\r\n");
    strOut.append(privKeyPkcs8);
    strOut.append("\r\n");

    delete privKey;


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }