(C#) Combine Timestamp Reply and Content File into a TimeStampData

Demonstrates how to combine a timestamp reply (RFC 3161) with a data file (any type of file) to create a TimeStampData structure (RFC 5544).

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

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

// Also see this example:
// Send a TimeStamp Request to a TimeStamp Authority and get the Response

// Load a timestamp reply file
Chilkat.BinData bdTsr = new Chilkat.BinData();
bool success = bdTsr.LoadFile("qa_data/tsd/sample.tsr");
if (success != true) {
    Debug.WriteLine("Failed to load timestamp reply file.");
    return;
}

// Load the tsr into an ASN.1 object.
Chilkat.Asn asnTsr = new Chilkat.Asn();
success = asnTsr.LoadEncoded(bdTsr.GetEncoded("base64"),"base64");
if (success != true) {
    Debug.WriteLine(asnTsr.LastErrorText);
    return;
}

// Get the timestamp reply as XML.
Chilkat.Xml xmlTsr = new Chilkat.Xml();
xmlTsr.LoadXml(asnTsr.AsnToXml());

// The timestamp reply XML begins like this:
// We'll want to remove the 1st "sequence" subtree.

//     <?xml version="1.0" encoding="utf-8"?>
//     <sequence>
//         <sequence>       <---- Remove this sub-tree.
//             <int>00</int>
//             <sequence>
//                 <utf8>Operation Okay</utf8>
//             </sequence>
//         </sequence>
//         <sequence>   
//             <oid>1.2.840.113549.1.7.2</oid>
//             <contextSpecific tag="0" constructed="1">
//             ...

// Remove the 1st sub-tree..
xmlTsr.RemoveChildByIndex(0);

// In this example, the data file we're combining with the timestamp into a timestampData is a .p7m.
// However, it can be any type of file (text or binary), it doesn't matter..
Chilkat.BinData bdContent = new Chilkat.BinData();
success = bdContent.LoadFile("qa_data/tsd/sample.p7m");
if (success != true) {
    Debug.WriteLine("Failed to load content file.");
    return;
}

// Begin building the TimeStampData.  
// We'll build as XML and then convert to ASN.1
Chilkat.Xml xml = new Chilkat.Xml();
xml.Tag = "sequence";
xml.UpdateChildContent("oid","1.2.840.113549.1.9.16.1.31");
xml.UpdateAttrAt("contextSpecific",true,"tag","0");
xml.UpdateAttrAt("contextSpecific",true,"constructed","1");
xml.UpdateChildContent("contextSpecific|sequence|int","01");
xml.UpdateChildContent("contextSpecific|sequence|octets",bdContent.GetEncoded("base64"));
xml.UpdateAttrAt("contextSpecific|sequence|contextSpecific",true,"tag","0");
xml.UpdateAttrAt("contextSpecific|sequence|contextSpecific",true,"constructed","1");

Chilkat.Xml xContext = xml.GetChildWithTag("contextSpecific|sequence|contextSpecific");
xContext.AddChildTree(xmlTsr);

// Convert the XML to ASN.1
Chilkat.Asn tsd = new Chilkat.Asn();
tsd.LoadAsnXml(xml.GetXml());

// Write the timestamped data to a file.
success = tsd.WriteBinaryDer("qa_output/sample.tsd");

// Alternatively, get the tsd ASN.1 as base64..
string tsdBase64 = tsd.GetEncodedDer("base64_mime");
Debug.WriteLine(tsdBase64);