(MFC) Convert Let's Encrypt PEM Files to a PFX

Demonstrates how to convert the .pem files provided by Let's Encrypt to a single PFX.

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

See Also: Using MFC CString in Chilkat

#include <CkStringBuilder.h>
#include <CkPfx.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    // Let's Encrypt provides four .pem files
    // 1. fullchain.pem
    // 2. privkey.pem
    // 3. cert.pem
    // 4. chain.pem

    // The cert.pem and chain.pem are redundant. 
    // The fullchain.pem is composed of the cert.pem and chain.pem.

    // To convert the PEM's to a single .pfx, we don't need the redundant data.
    // The privkey.pem and fullchain.pem provide the required data.
    // We can ignore cert.pem and chain.pem (because those certs are already found in fullchain.pem).

    // We need a single .pem file that contains both the private key, the cert,
    // and the certs in the chain of authentication.
    // Let's combine priveky.pem and fullchain.pem into a single .pem

    CkStringBuilder sbPem;
    bool success = sbPem.LoadFile("qa_data/pem/lets_encrypt/privkey.pem","utf-8");
    if (success == false) {
        strOut.append("Failed to load privkey.pem");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // To be safe, append a blank line..
    sbPem.AppendLine("",false);

    CkStringBuilder sbFullChainPem;
    success = sbFullChainPem.LoadFile("qa_data/pem/lets_encrypt/fullchain.pem","utf-8");
    if (success == false) {
        strOut.append("Failed to load fullchain.pem");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Append the full cert chain PEM to the private key PEM.
    sbPem.AppendSb(sbFullChainPem);

    // Load the combined PEM into a Chilkat PFX object.
    CkPfx pfx;
    success = pfx.LoadPem(sbPem.getAsString(),"no password required");
    if (success == false) {
        strOut.append(pfx.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Write the PFX w/ a password.
    const char *pfxPassword = "secret";
    success = pfx.ToFile(pfxPassword,"qa_output/sample.pfx");
    if (success == false) {
        strOut.append(pfx.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

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


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }