B4X

Combine Timestamp Reply and Content File into a TimeStampData

See more ASN.1 Examples

Demonstrates how to combine a timestamp reply (RFC 3161) with a data file (any type of file) to create a TimeStampData structure (RFC 5544). B4X

Dim success As Boolean = False

'  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
Dim bdTsr As ChilkatBinData
bdTsr.Initialize
success = bdTsr.LoadFile("qa_data/tsd/sample.tsr")
If success <> True Then
    Log("Failed to load timestamp reply file.")
    Return
End If


'  Load the tsr into an ASN.1 object.
Dim asnTsr As ChilkatAsn
asnTsr.Initialize
success = asnTsr.LoadEncoded(bdTsr.GetEncoded("base64"), "base64")
If success <> True Then
    Log(asnTsr.LastErrorText)
    Return
End If


'  Get the timestamp reply as XML.
Dim xmlTsr As ChilkatXml
xmlTsr.Initialize
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..
Dim bdContent As ChilkatBinData
bdContent.Initialize
success = bdContent.LoadFile("qa_data/tsd/sample.p7m")
If success <> True Then
    Log("Failed to load content file.")
    Return
End If


'  Begin building the TimeStampData.  
'  We'll build as XML and then convert to ASN.1
Dim xml As ChilkatXml
xml.Initialize
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")

Dim xContext As ChilkatXml = xml.GetChildWithTag("contextSpecific|sequence|contextSpecific")
xContext.AddChildTree(xmlTsr)


'  Convert the XML to ASN.1
Dim tsd As ChilkatAsn
tsd.Initialize
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..
Dim tsdBase64 As String = tsd.GetEncodedDer("base64_mime")
Log(tsdBase64)