Use Certificate and Private Key PEM Files to Create a Digital Signature

Demonstrates how to load a digital certificate from a PEM file, load it's corresponding private key from a PEM file, save the private key to a key container (if necessary), link the certificate to the key container, and use it to create a digital signature.

Downloads:

MS Windows Visual C/C++ Libraries

Linux/CentOS C/C++ Libraries

MAC OS X C/C++ Libraries

Solaris C/C++ Libraries

C++ Builder Libraries

// Needs #include <CkCert.h>
// Needs #include <CkPrivateKey.h>
// Needs #include <CkCrypt2.h>

    CkString strOut;

    CkCert cert;

    //  Load the cert from a PEM file;
    cert.LoadFromFile("cert.pem");

    CkPrivateKey pkey;

    //  Load the private key from an RSA PEM file:
    pkey.LoadPemFile("pkey_rsa.pem");

    bool success;

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

    //  Use Chilkat Crypt (a non-freeware component) to create
    //  a digital signature using the certificate w/ private key:
    CkCrypt2 crypt;

    //  Any string argument automatically begins the 30-day trial.

    success = crypt.UnlockComponent("30-day trial");
    if (success != true) {
        strOut.append(crypt.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    //  Tell the crypt component to use this cert.
    crypt.SetSigningCert(cert);

    //  A PKCS7 signature for any type of file content can be created:
    success = crypt.CreateP7S("license.rtf","license.p7s");
    if (success == false) {
        strOut.append(crypt.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append(crypt.lastErrorText());
    strOut.append("\r\n");

    //  Verify and restore the original file:
    crypt.SetVerifyCert(cert);

    success = crypt.VerifyP7S("license.rtf","license.p7s");
    if (success == false) {
        strOut.append(crypt.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append("Success!\r\n");



    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());