(.NET Core C#) Get PDF Signer Certs

See more PDF Signatures Examples

This example demonstrates how to validate the signatures in a PDF and also shows how to get each signature's signer certificate.

Note: This example requires Chilkat v9.5.0.87 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 that has cryptographic signatures to be validated
bool success = pdf.LoadFile("qa_data/pdf/sign_testing_1/helloSigned2.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

// Each time we verify a signature, information about the signature is written into
// sigInfo (replacing whatever sigInfo previously contained).
Chilkat.JsonObject sigInfo = new Chilkat.JsonObject();

// Iterate over each signature and validate each.
int numSignatures = pdf.NumSignatures;
bool validated = false;
Chilkat.Cert cert = new Chilkat.Cert();
int i = 0;
while (i < numSignatures) {
    validated = pdf.VerifySignature(i,sigInfo);
    Debug.WriteLine("Signature " + Convert.ToString(i) + " validated: " + Convert.ToString(validated));

    // The GetSignerCert method was added in Chilkat v9.5.0.87
    // After calling VerifySignature, you can get the signer certificate by calling
    // GetSignerCert with the same index. 
    success = pdf.GetSignerCert(i,cert);
    if (success != false) {
        Debug.WriteLine("PDF signer certificate: " + cert.SubjectDN);
    }

    i = i + 1;
}

Debug.WriteLine("Finished.");