VBScript

Extract TSTInfo from RFC3161 Timestamp Reply

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Sends an RFC 3161 timestamp request to a TSA (Timestamp Authority) server and converts the timestamp reply to XML, and then extracts the TSTInfo from the XML and converts it to XML. VBScript

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

success = 0

' Note: Requires Chilkat v9.5.0.75 or greater.

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

' First sha-256 hash the data that is to be timestamped.
' In this example, the data is the string "Hello World"

set crypt = CreateObject("Chilkat.Crypt2")
crypt.HashAlgorithm = "sha256"
crypt.EncodingMode = "base64"
base64Hash = crypt.HashFileENC("qa_data/hamlet.xml")

set http = CreateObject("Chilkat.Http")

set requestToken = CreateObject("Chilkat.BinData")
optionalPolicyOid = ""
addNonce = 0
requestTsaCert = 1

' Create a time-stamp request token
success = http.CreateTimestampRequest("sha256",base64Hash,optionalPolicyOid,addNonce,requestTsaCert,requestToken)
If (success = 0) Then
    outFile.WriteLine(http.LastErrorText)
    WScript.Quit
End If

' Send the time-stamp request token to the TSA.
' This is the equivalent of the following CURL command:
' curl -H "Content-Type: application/timestamp-query" --data-binary '@file.tsq' http://timestamp.digicert.com > file.tsr
tsaUrl = "http://timestamp.digicert.com"
set resp = CreateObject("Chilkat.HttpResponse")
success = http.HttpBd("POST",tsaUrl,requestToken,"application/timestamp-query",resp)
If (success = 0) Then
    outFile.WriteLine(http.LastErrorText)
    WScript.Quit
End If

' Get the timestamp reply from the HTTP response object.
set timestampReply = CreateObject("Chilkat.BinData")
success = resp.GetBodyBd(timestampReply)

' Convert the binary timestamp reply to XML
set asn = CreateObject("Chilkat.Asn")
success = asn.LoadBd(timestampReply)
If (success = 0) Then
    outFile.WriteLine(asn.LastErrorText)
    WScript.Quit
End If

set xml = CreateObject("Chilkat.Xml")
success = xml.LoadXml(asn.AsnToXml())

' Extract the TSTInfo from the XML.
' The TSTInfo is this base64 encoded ASN.1 

' TSTInfo ::= SEQUENCE  {
'    version                      INTEGER  { v1(1) },
'    policy                       TSAPolicyId,
'    messageImprint               MessageImprint,
'      -- MUST have the same value as the similar field in
'      -- TimeStampReq
'    serialNumber                 INTEGER,
'     -- Time-Stamping users MUST be ready to accommodate integers
'     -- up to 160 bits.
'    genTime                      GeneralizedTime,
'    accuracy                     Accuracy                 OPTIONAL,
'    ordering                     BOOLEAN             DEFAULT FALSE,
'    nonce                        INTEGER                  OPTIONAL,
'      -- MUST be present if the similar field was present
'      -- in TimeStampReq.  In that case it MUST have the same value.
'    tsa                          [0] GeneralName          OPTIONAL,
'    extensions                   [1] IMPLICIT Extensions   OPTIONAL  }

tstInfoBase64 = xml.GetChildContent("sequence[1]|contextSpecific|sequence|sequence|contextSpecific|octets")

set bdTstInfo = CreateObject("Chilkat.BinData")
success = bdTstInfo.AppendEncoded(tstInfoBase64,"base64")

set asnTstInfo = CreateObject("Chilkat.Asn")
success = asnTstInfo.LoadBd(bdTstInfo)
If (success = 0) Then
    outFile.WriteLine(asnTstInfo.LastErrorText)
    WScript.Quit
End If

set xmlTstInfo = CreateObject("Chilkat.Xml")
success = xmlTstInfo.LoadXml(asnTstInfo.AsnToXml())
outFile.WriteLine(xmlTstInfo.GetXml())

' Here's the TSTInfo XML:

' <?xml version="1.0" encoding="utf-8"?>
' <sequence>
'     <int>01</int>
'     <oid>2.16.840.1.114412.7.1</oid>
'     <sequence>
'         <sequence>
'             <oid>2.16.840.1.101.3.4.2.1</oid>
'             <null/>
'         </sequence>
'         <octets>4sRRyWOzC7EOic4fQ9+Op1pa10DbgoBGjBvkq09LZmE=</octets>
'     </sequence>
'     <int>00AD2C86E49872597B60F87D5C54BCFFAE</int>
'     <universal tag="24" constructed="0">MjAyMzAzMTYxMTQ5NTJa</universal>
' </sequence>

'    The genTime (GeneralizedTime) is contained in the final "universal" XML element and is 
'    in base64. It is the time at which the time-stamp token has been created by
'    the TSA. After decoding from base64, it is:
' 
'    The syntax is: YYYYMMDDhhmmss[.s...]Z
'    Example: 19990609001326.34352Z

set sbGenTime = CreateObject("Chilkat.StringBuilder")
success = sbGenTime.DecodeAndAppend(xmlTstInfo.GetChildContent("universal"),"base64","utf-8")
outFile.WriteLine(sbGenTime.GetAsString())

' Result:
' 20230316115718Z

outFile.Close