C#

Convert Let's Encrypt PEM Files to a PFX

See more PFX/P12 Examples

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

bool success = false;

//  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

Chilkat.StringBuilder sbPem = new Chilkat.StringBuilder();
success = sbPem.LoadFile("qa_data/pem/lets_encrypt/privkey.pem","utf-8");
if (success == false) {
    Debug.WriteLine("Failed to load privkey.pem");
    return;
}

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

Chilkat.StringBuilder sbFullChainPem = new Chilkat.StringBuilder();
success = sbFullChainPem.LoadFile("qa_data/pem/lets_encrypt/fullchain.pem","utf-8");
if (success == false) {
    Debug.WriteLine("Failed to load fullchain.pem");
    return;
}

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

//  Load the combined PEM into a Chilkat PFX object.
Chilkat.Pfx pfx = new Chilkat.Pfx();
success = pfx.LoadPem(sbPem.GetAsString(),"no password required");
if (success == false) {
    Debug.WriteLine(pfx.LastErrorText);
    return;
}

//  Write the PFX w/ a password.
string pfxPassword = "secret";
success = pfx.ToFile(pfxPassword,"qa_output/sample.pfx");
if (success == false) {
    Debug.WriteLine(pfx.LastErrorText);
    return;
}

Debug.WriteLine("Success!");