(C#) Sign PDF in the Cloud using AWS CloudHSM

See more Signing in the Cloud Examples

Demonstrates how to sign a PDF using AWS CloudHSM. The signing of the hash happens on a hardware token in AWS CloudHSM. Everything else involving the updating the PDF to add the signature happens locally within Chilkat.

Note: This example requires Chilkat v9.5.0.96 or greater.

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// 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();

// Provide the path to the AWS CloudHSM PKCS11 driver.
// This example runs on Windows, so we'll provide the CloudHSM DLL.
// If your code runs on Linux, the CloudHSM driver might be at /opt/cloudhsm/lib/libcloudhsm_pkcs11.so
pkcs11.SharedLibPath = "C:\\Program Files\\Amazon\\CloudHSM\\lib\\cloudhsm_pkcs11.dll";

// Your PIN should be a string containing your crypto user's login and password, with a colon char delimiting.
// See https://docs.aws.amazon.com/cloudhsm/latest/userguide/pkcs11-pin.html
string pin = "user:password";
int userType = 1;

// Establish a PKCS logged-on session using the driver (.so, .dylib, or .dll) as specified in the SharedLibPath above.
bool success = pkcs11.QuickSession(userType,pin);
if (success == false) {
    Debug.WriteLine(pkcs11.LastErrorText);
    return;
}

Chilkat.Cert cert = new Chilkat.Cert();
success = cert.LoadFromFile("qa_data/certs/myCert.cer");
if (success == false) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

// Tell the certificate to link with the PKCS11 session.
// The cert's private key should be installed on the CloudHSM.
// If there are multiple private keys on the CloudHSM, then Chilkat will automatically
// locate and use the private key corresponding to the certificate.
success = cert.LinkPkcs11(pkcs11);
if (success == false) {
    Debug.WriteLine(cert.LastErrorText);
    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 = pdf.SignPdf(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.");