(MFC) PKCS7 Sign Text using RSA 2048, SHA256, Base64 Output

Demonstrates how to sign text using 2048-bit RSA with SHA256, producing PKCS#7 output in Base64. The certificate w/ private key used for signing is loaded from a .p12/.pfx file.

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

See Also: Using MFC CString in Chilkat

#include <CkCert.h>
#include <CkCrypt2.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkCert cert;

    // Load the cert and private key.  Whatever the private key happens to be,
    // such as RSA or ECC, then Chilkat will use it.  If the private key is 
    // a 2048-bit RSA key, then that's what will be used..
    bool success = cert.LoadPfxFile("qa_data/pfx/myCertAndKey.p12","password");
    if (success != true) {
        strOut.append(cert.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkCrypt2 crypt;

    success = crypt.SetSigningCert(cert);
    if (success != true) {
        strOut.append(crypt.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Use SHA-256
    crypt.put_HashAlgorithm("sha256");

    // Hash the utf-8 byte representation of the string
    crypt.put_Charset("utf-8");

    // Return the result in base64
    crypt.put_EncodingMode("base64");

    // Sign some text..
    const char *textToSign = "This is the text to be hashed and signed.";
    const char *sigBase64 = crypt.opaqueSignStringENC(textToSign);
    if (crypt.get_LastMethodSuccess() != true) {
        strOut.append(crypt.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append(sigBase64);
    strOut.append("\r\n");

    // The result:
    // MIIS2wYJKoZIhvcNAQc ... zGeeY4Oxg==


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }