Tcl Requires Chilkat v11.0.0+

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. Tcl

load ./chilkat.dll

set 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 [new_CkCrypt2]

CkCrypt2_put_HashAlgorithm $crypt "sha256"
CkCrypt2_put_EncodingMode $crypt "base64"
set base64Hash [CkCrypt2_hashFileENC $crypt "qa_data/hamlet.xml"]

set http [new_CkHttp]

set requestToken [new_CkBinData]

set optionalPolicyOid ""
set addNonce 0
set requestTsaCert 1

#  Create a time-stamp request token
set success [CkHttp_CreateTimestampRequest $http "sha256" $base64Hash $optionalPolicyOid $addNonce $requestTsaCert $requestToken]
if {$success == 0} then {
    puts [CkHttp_lastErrorText $http]
    delete_CkCrypt2 $crypt
    delete_CkHttp $http
    delete_CkBinData $requestToken
    exit
}

#  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
set tsaUrl "http://timestamp.digicert.com"
set resp [new_CkHttpResponse]

set success [CkHttp_HttpBd $http "POST" $tsaUrl $requestToken "application/timestamp-query" $resp]
if {$success == 0} then {
    puts [CkHttp_lastErrorText $http]
    delete_CkCrypt2 $crypt
    delete_CkHttp $http
    delete_CkBinData $requestToken
    delete_CkHttpResponse $resp
    exit
}

#  Get the timestamp reply from the HTTP response object.
set timestampReply [new_CkBinData]

CkHttpResponse_GetBodyBd $resp $timestampReply

#  Convert the binary timestamp reply to XML
set asn [new_CkAsn]

set success [CkAsn_LoadBd $asn $timestampReply]
if {$success == 0} then {
    puts [CkAsn_lastErrorText $asn]
    delete_CkCrypt2 $crypt
    delete_CkHttp $http
    delete_CkBinData $requestToken
    delete_CkHttpResponse $resp
    delete_CkBinData $timestampReply
    delete_CkAsn $asn
    exit
}

set xml [new_CkXml]

set success [CkXml_LoadXml $xml [CkAsn_asnToXml $asn]]

#  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  }

set tstInfoBase64 [CkXml_getChildContent $xml "sequence[1]|contextSpecific|sequence|sequence|contextSpecific|octets"]

set bdTstInfo [new_CkBinData]

CkBinData_AppendEncoded $bdTstInfo $tstInfoBase64 "base64"

set asnTstInfo [new_CkAsn]

set success [CkAsn_LoadBd $asnTstInfo $bdTstInfo]
if {$success == 0} then {
    puts [CkAsn_lastErrorText $asnTstInfo]
    delete_CkCrypt2 $crypt
    delete_CkHttp $http
    delete_CkBinData $requestToken
    delete_CkHttpResponse $resp
    delete_CkBinData $timestampReply
    delete_CkAsn $asn
    delete_CkXml $xml
    delete_CkBinData $bdTstInfo
    delete_CkAsn $asnTstInfo
    exit
}

set xmlTstInfo [new_CkXml]

set success [CkXml_LoadXml $xmlTstInfo [CkAsn_asnToXml $asnTstInfo]]
puts [CkXml_getXml $xmlTstInfo]

#  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 [new_CkStringBuilder]

CkStringBuilder_DecodeAndAppend $sbGenTime [CkXml_getChildContent $xmlTstInfo "universal"] "base64" "utf-8"
puts [CkStringBuilder_getAsString $sbGenTime]

#  Result:
#  20230316115718Z

delete_CkCrypt2 $crypt
delete_CkHttp $http
delete_CkBinData $requestToken
delete_CkHttpResponse $resp
delete_CkBinData $timestampReply
delete_CkAsn $asn
delete_CkXml $xml
delete_CkBinData $bdTstInfo
delete_CkAsn $asnTstInfo
delete_CkXml $xmlTstInfo
delete_CkStringBuilder $sbGenTime