(.NET Core C#) Sign PDF in the Cloud using Azure Key Vault

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Demonstrates how to sign a PDF using Azure Key Vault. The signing of the hash happens in the Cloud on Azure Key Vault. 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.

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

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

// Options for signing are specified in JSON.
Chilkat.JsonObject json = new Chilkat.JsonObject();

// Optionally create an LTV-enabled signature
json.UpdateBool("ltvOcsp",true);

// Define the appearance of the signature.
json.UpdateInt("page",1);
json.UpdateString("appearance.y","top");
json.UpdateString("appearance.x","left");
json.UpdateString("appearance.fontScale","10.0");
json.UpdateString("appearance.text[0]","Digitally signed by: cert_cn");
json.UpdateString("appearance.text[1]","current_dt");
json.UpdateString("appearance.text[2]","This is an LTV-enabled signature.");

// Load the certificate used for signing.  The certificate's private key is stored in 
// the Azure Key Vault.
// However, we still need the certificate locally (without private key).
Chilkat.Cert cert = new Chilkat.Cert();
success = cert.LoadFromFile("qa_data/certs/myCert.cer");
if (success == false) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

// Here's a screenshot of our certificate with private key on Azure Key Vault:


// To sign using the Azure Key Vault, 
// add the following lines of code to specify your authentication credentials,
// and the name of the certificate w/ private key on the Azure server to be used.
Chilkat.JsonObject jsonAzure = new Chilkat.JsonObject();
// Set the "service" equal to "azure_keyvault" to tell Chilkat to use Azure Key Vault for signing.
jsonAzure.UpdateString("service","azure_keyvault");
jsonAzure.UpdateString("client_id","APP_ID");
jsonAzure.UpdateString("client_secret","APP_PASSWORD");
jsonAzure.UpdateString("tenant_id","TENANT_ID");
// In the above screenshot, our vault name is "kvchilkat".  You will use your vault name.
jsonAzure.UpdateString("vault_name","VAULT_NAME");
// In the above screenshot, our cert name is "ChilkatTest1".  You will use your cert name.
jsonAzure.UpdateString("cert_name","CERT_NAME");
// In the above screenshot, our cert version is "63b94a23389546ecbc8eb6208a1bef37".  You will use your cert version.
jsonAzure.UpdateString("cert_version","CERT_VERSION");
success = cert.SetCloudSigner(jsonAzure);

// Tell the pdf object to use the certificate for signing (and for Azure Key Vault to do the actual signing of the hash).
success = pdf.SetSigningCert(cert);
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

// Chilkat will build the signed PDF locally, but will (internally) use Azure Key Vault
// to do the RSA (or EC) sign hash operation.
success = pdf.SignPdf(json,"qa_output/hello_ltv_signed.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Debug.WriteLine("PDF Cloud Signing using Azure Key Vault Successful.");