Visual FoxPro

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. Visual FoxPro

LOCAL lnSuccess
LOCAL loCrypt
LOCAL lcBase64Hash
LOCAL loHttp
LOCAL loRequestToken
LOCAL lcOptionalPolicyOid
LOCAL lnAddNonce
LOCAL lnRequestTsaCert
LOCAL lcTsaUrl
LOCAL loResp
LOCAL loTimestampReply
LOCAL loAsn
LOCAL loXml
LOCAL lcTstInfoBase64
LOCAL loBdTstInfo
LOCAL loAsnTstInfo
LOCAL loXmlTstInfo
LOCAL loSbGenTime

lnSuccess = 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"

loCrypt = CreateObject('Chilkat.Crypt2')
loCrypt.HashAlgorithm = "sha256"
loCrypt.EncodingMode = "base64"
lcBase64Hash = loCrypt.HashFileENC("qa_data/hamlet.xml")

loHttp = CreateObject('Chilkat.Http')

loRequestToken = CreateObject('Chilkat.BinData')
lcOptionalPolicyOid = ""
lnAddNonce = 0
lnRequestTsaCert = 1

* Create a time-stamp request token
lnSuccess = loHttp.CreateTimestampRequest("sha256",lcBase64Hash,lcOptionalPolicyOid,lnAddNonce,lnRequestTsaCert,loRequestToken)
IF (lnSuccess = 0) THEN
    ? loHttp.LastErrorText
    RELEASE loCrypt
    RELEASE loHttp
    RELEASE loRequestToken
    CANCEL
ENDIF

* 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
lcTsaUrl = "http://timestamp.digicert.com"
loResp = CreateObject('Chilkat.HttpResponse')
lnSuccess = loHttp.HttpBd("POST",lcTsaUrl,loRequestToken,"application/timestamp-query",loResp)
IF (lnSuccess = 0) THEN
    ? loHttp.LastErrorText
    RELEASE loCrypt
    RELEASE loHttp
    RELEASE loRequestToken
    RELEASE loResp
    CANCEL
ENDIF

* Get the timestamp reply from the HTTP response object.
loTimestampReply = CreateObject('Chilkat.BinData')
loResp.GetBodyBd(loTimestampReply)

* Convert the binary timestamp reply to XML
loAsn = CreateObject('Chilkat.Asn')
lnSuccess = loAsn.LoadBd(loTimestampReply)
IF (lnSuccess = 0) THEN
    ? loAsn.LastErrorText
    RELEASE loCrypt
    RELEASE loHttp
    RELEASE loRequestToken
    RELEASE loResp
    RELEASE loTimestampReply
    RELEASE loAsn
    CANCEL
ENDIF

loXml = CreateObject('Chilkat.Xml')
lnSuccess = loXml.LoadXml(loAsn.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  }

lcTstInfoBase64 = loXml.GetChildContent("sequence[1]|contextSpecific|sequence|sequence|contextSpecific|octets")

loBdTstInfo = CreateObject('Chilkat.BinData')
loBdTstInfo.AppendEncoded(lcTstInfoBase64,"base64")

loAsnTstInfo = CreateObject('Chilkat.Asn')
lnSuccess = loAsnTstInfo.LoadBd(loBdTstInfo)
IF (lnSuccess = 0) THEN
    ? loAsnTstInfo.LastErrorText
    RELEASE loCrypt
    RELEASE loHttp
    RELEASE loRequestToken
    RELEASE loResp
    RELEASE loTimestampReply
    RELEASE loAsn
    RELEASE loXml
    RELEASE loBdTstInfo
    RELEASE loAsnTstInfo
    CANCEL
ENDIF

loXmlTstInfo = CreateObject('Chilkat.Xml')
lnSuccess = loXmlTstInfo.LoadXml(loAsnTstInfo.AsnToXml())
? loXmlTstInfo.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

loSbGenTime = CreateObject('Chilkat.StringBuilder')
loSbGenTime.DecodeAndAppend(loXmlTstInfo.GetChildContent("universal"),"base64","utf-8")
? loSbGenTime.GetAsString()

* Result:
* 20230316115718Z

RELEASE loCrypt
RELEASE loHttp
RELEASE loRequestToken
RELEASE loResp
RELEASE loTimestampReply
RELEASE loAsn
RELEASE loXml
RELEASE loBdTstInfo
RELEASE loAsnTstInfo
RELEASE loXmlTstInfo
RELEASE loSbGenTime