Delphi DLL 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. Delphi DLL

var
success: Boolean;
crypt: HCkCrypt2;
base64Hash: PWideChar;
http: HCkHttp;
requestToken: HCkBinData;
optionalPolicyOid: PWideChar;
addNonce: Boolean;
requestTsaCert: Boolean;
tsaUrl: PWideChar;
resp: HCkHttpResponse;
timestampReply: HCkBinData;
asn: HCkAsn;
xml: HCkXml;
tstInfoBase64: PWideChar;
bdTstInfo: HCkBinData;
asnTstInfo: HCkAsn;
xmlTstInfo: HCkXml;
sbGenTime: HCkStringBuilder;

begin
success := False;

//  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"

crypt := CkCrypt2_Create();
CkCrypt2_putHashAlgorithm(crypt,'sha256');
CkCrypt2_putEncodingMode(crypt,'base64');
base64Hash := CkCrypt2__hashFileENC(crypt,'qa_data/hamlet.xml');

http := CkHttp_Create();

requestToken := CkBinData_Create();
optionalPolicyOid := '';
addNonce := False;
requestTsaCert := True;

//  Create a time-stamp request token
success := CkHttp_CreateTimestampRequest(http,'sha256',base64Hash,optionalPolicyOid,addNonce,requestTsaCert,requestToken);
if (success = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

//  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';
resp := CkHttpResponse_Create();
success := CkHttp_HttpBd(http,'POST',tsaUrl,requestToken,'application/timestamp-query',resp);
if (success = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

//  Get the timestamp reply from the HTTP response object.
timestampReply := CkBinData_Create();
CkHttpResponse_GetBodyBd(resp,timestampReply);

//  Convert the binary timestamp reply to XML
asn := CkAsn_Create();
success := CkAsn_LoadBd(asn,timestampReply);
if (success = False) then
  begin
    Memo1.Lines.Add(CkAsn__lastErrorText(asn));
    Exit;
  end;

xml := CkXml_Create();
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  }

tstInfoBase64 := CkXml__getChildContent(xml,'sequence[1]|contextSpecific|sequence|sequence|contextSpecific|octets');

bdTstInfo := CkBinData_Create();
CkBinData_AppendEncoded(bdTstInfo,tstInfoBase64,'base64');

asnTstInfo := CkAsn_Create();
success := CkAsn_LoadBd(asnTstInfo,bdTstInfo);
if (success = False) then
  begin
    Memo1.Lines.Add(CkAsn__lastErrorText(asnTstInfo));
    Exit;
  end;

xmlTstInfo := CkXml_Create();
success := CkXml_LoadXml(xmlTstInfo,CkAsn__asnToXml(asnTstInfo));
Memo1.Lines.Add(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

sbGenTime := CkStringBuilder_Create();
CkStringBuilder_DecodeAndAppend(sbGenTime,CkXml__getChildContent(xmlTstInfo,'universal'),'base64','utf-8');
Memo1.Lines.Add(CkStringBuilder__getAsString(sbGenTime));

//  Result:
//  20230316115718Z

CkCrypt2_Dispose(crypt);
CkHttp_Dispose(http);
CkBinData_Dispose(requestToken);
CkHttpResponse_Dispose(resp);
CkBinData_Dispose(timestampReply);
CkAsn_Dispose(asn);
CkXml_Dispose(xml);
CkBinData_Dispose(bdTstInfo);
CkAsn_Dispose(asnTstInfo);
CkXml_Dispose(xmlTstInfo);
CkStringBuilder_Dispose(sbGenTime);