(C# UWP/WinRT) PKCS11 Sign PDF using Certificate and Private Key on Smart Card / USB Token

See more PKCS11 Examples

Sample code showing how to use PKCS11 to sign a PDF with a certificate and private key stored on a smart card or USB token.

Note: This example requires Chilkat v9.5.0.88 or later.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

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

// Note: Chilkat's PKCS11 implementation runs on Windows, Linux, Mac OS X, and other supported operating systems.

Chilkat.Pkcs11 pkcs11 = new Chilkat.Pkcs11();

// This example is tested on Windows using a Giesecke and Devrient Sm@rtCafe Expert 3.2 smart card.
pkcs11.SharedLibPath = "aetpkss1.dll";

bool success = pkcs11.Initialize();
if (success == false) {
    Debug.WriteLine(pkcs11.LastErrorText);
    return;
}

// We need to call Discover to get the slot ID.
bool onlyTokensPresent = true;
Chilkat.JsonObject jsonPkcs11 = new Chilkat.JsonObject();
success = pkcs11.Discover(onlyTokensPresent,jsonPkcs11);
if (success == false) {
    Debug.WriteLine(pkcs11.LastErrorText);
    return;
}

// Make sure we have at least one slot.
if (jsonPkcs11.SizeOfArray("slot") <= 0) {
    Debug.WriteLine("No occuplied slots.");
    return;
}

// Get the ID of the 1st slot
int slotID = jsonPkcs11.IntOf("slot[0].id");

// Open a session.
bool readWrite = true;
success = pkcs11.OpenSession(slotID,readWrite);
if (success == false) {
    Debug.WriteLine(pkcs11.LastErrorText);
    return;
}

// Make it an authenticated session by calling Login.
int userType = 1;
// Make sure to use the correct PIN for your smart card..
string pin = "0000";
success = pkcs11.Login(userType,pin);
if (success == false) {
    Debug.WriteLine(pkcs11.LastErrorText);
    success = pkcs11.CloseSession();
    return;
}

// Get the certificate (on the smart card) that has a private key.
Chilkat.Cert cert = new Chilkat.Cert();
success = pkcs11.FindCert("privateKey","",cert);
if (success == true) {
    Debug.WriteLine("Cert with private key: " + cert.SubjectCN);
}
else {
    Debug.WriteLine("No certificates having a private key were found.");
    success = pkcs11.CloseSession();
    return;
}

// --------------------------------------------------------------------------
// At this point, we have the cert to be used for signing.
// Our PDF signing code is the same as for a cert obtained from any other source..

Chilkat.Pdf pdf = new Chilkat.Pdf();

// Load a PDF to be signed.
success = pdf.LoadFile("qa_data/pdf/hello.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    success = pkcs11.CloseSession();
    return;
}

Chilkat.JsonObject json = new Chilkat.JsonObject();

json.UpdateInt("page",1);
json.UpdateString("appearance.y","top");
json.UpdateString("appearance.x","left");
json.UpdateString("appearance.fontScale","10.0");
json.UpdateString("signingAlgorithm","pss");
json.UpdateString("hashAlgorithm","sha256");

int i = 0;
json.I = i;
json.UpdateString("appearance.text[i]","Digitaly signed by: Xyz Widgets, Inc.");
i = i + 1;
json.I = i;
json.UpdateString("appearance.text[i]","current_dt");
i = i + 1;
json.I = i;
json.UpdateString("appearance.text[i]","blah blah blah");

// The certificate is internally linked to the Pkcs11 object, which is currently in an authenticated session.
success = pdf.SetSigningCert(cert);

success = await pdf.SignPdfAsync(json,"qa_output/out.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    success = pkcs11.CloseSession();
    return;
}

// --------------------------------------------------------------------------

// Revert to an unauthenticated session by calling Logout.
success = pkcs11.Logout();
if (success == false) {
    Debug.WriteLine(pkcs11.LastErrorText);
    success = pkcs11.CloseSession();
    return;
}

// When finished, close the session.
// It is important to close the session (memory leaks will occur if the session is not properly closed).
success = pkcs11.CloseSession();
if (success == false) {
    Debug.WriteLine(pkcs11.LastErrorText);
    return;
}

Debug.WriteLine("Success.");