(.NET Core C#) Create a CAdES-T Signature

Demonstrates how to create a signature with an external timestamp that certifies the time of signing. This requires an online TSA (Time Stamping Authority) service that is capable of producing RFC 3161 compliant timestamps.

Note: This example requires Chilkat v9.5.0.78 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.Crypt2 crypt = new Chilkat.Crypt2();

// This example will use a certificate + private key from a .pfx/.p12 file.
// On Windows systems, it is also possible to use certs on smartcards/usb tokens or certs pre-installed in the Windows registry.
Chilkat.Cert cert = new Chilkat.Cert();

string pfxPath = "qa_data/pfx/myCertAndKey.p12";
string pfxPassword = "test123";

bool success = cert.LoadPfxFile(pfxPath,pfxPassword);
if (success != true) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

success = crypt.SetSigningCert(cert);

// Use SHA-256 rather than the default of SHA-1
crypt.HashAlgorithm = "sha256";

// Create JSON that tells Chilkat what signing attributes to include:
Chilkat.JsonObject attrs = new Chilkat.JsonObject();
attrs.UpdateBool("contentType",true);
attrs.UpdateBool("signingTime",true);
attrs.UpdateBool("messageDigest",true);
attrs.UpdateBool("signingCertificateV2",true);

// A CAdES-T signature is one that includes a timestampToken created by an online TSA (time stamping authority).
// We must include the TSA's URL, as well as a few options to indicate what is desired.
// Except for the TSA URL, the options shown here are typically what you would need.
attrs.UpdateBool("timestampToken.enabled",true);
attrs.UpdateString("timestampToken.tsaUrl","https://freetsa.org/tsr");
attrs.UpdateBool("timestampToken.addNonce",false);
attrs.UpdateBool("timestampToken.requestTsaCert",true);
attrs.UpdateString("timestampToken.hashAlg","sha256");

crypt.SigningAttributes = attrs.Emit();

string inFile = "qa_data/json/sample.json";
string outFile = "qa_output/sample_cades_t.p7m";

// This creates the CAdES-T signature.  During the signature creation, it
// communicates with the TSA to get a timestampToken.
success = crypt.CreateP7M(inFile,outFile);
if (success != true) {
    Debug.WriteLine(crypt.LastErrorText);
    return;
}

Debug.WriteLine("Success.");