C#

Duplicate openssl pkcs12 –export –in certfile.cer –inkey certfile.key –out certfile.pfx

See more OpenSSL Examples

How to create a PKCS12 (.p12 or .pfx) from a certificate file and private key file: Demonstrates how to duplicate this OpenSSL command:

Duplicate openssl pkcs12 –export –in certfile.cer –inkey certfile.key –out certfile.pfx

C#

bool success = false;

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

Chilkat.PrivateKey pkey = new Chilkat.PrivateKey();

// Load the private key from the file.
success = pkey.LoadAnyFormatFile("certFile.key","");
if (success != true) {
    Debug.WriteLine(pkey.LastErrorText);
    return;
}

Chilkat.Cert cert = new Chilkat.Cert();
// The LoadFromFile method auto-recognizes the format...
success = cert.LoadFromFile("certfile.cer");
if (success != true) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

// We'll need a cert chain object to create the PKCS12, so get it
// from the cert.  
Chilkat.CertChain certChain = null;
certChain = cert.GetCertChain();
if (!cert.LastMethodSuccess) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

// Create the PFX object, add the cert and private key, and write to a .pfx file.
Chilkat.Pfx pfx = new Chilkat.Pfx();

// The cert(s) are automatically added in the call to AddPrivateKey
success = pfx.AddPrivateKey(pkey,certChain);
if (success != true) {
    Debug.WriteLine(pfx.LastErrorText);
    return;
}

// Write the .pfx to a file.
string password = "myPassword";
success = pfx.ToFile(password,"certfile.pfx");
if (success != true) {
    Debug.WriteLine(pfx.LastErrorText);
    return;
}

Debug.WriteLine("Success.");