Lua 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. Lua

local chilkat = require("chilkat")

-- 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"

local crypt = chilkat.Crypt2.new()
crypt.hash_algorithm = "sha256"
crypt.encoding_mode = "base64"
local base64Hash = crypt:hash_file_enc("qa_data/hamlet.xml")

local http = chilkat.Http.new()

local requestToken = chilkat.BinData.new()
local optionalPolicyOid = ""
local addNonce = false
local requestTsaCert = true

-- Create a time-stamp request token
local success = http:create_timestamp_request("sha256", base64Hash, optionalPolicyOid, addNonce, requestTsaCert, requestToken)
if not success then
    print(http.last_error_text)
    return
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
local tsaUrl = "http://timestamp.digicert.com"
local resp = chilkat.HttpResponse.new()
success = http:http_bd("POST", tsaUrl, requestToken, "application/timestamp-query", resp)
if not success then
    print(http.last_error_text)
    return
end

-- Get the timestamp reply from the HTTP response object.
local timestampReply = chilkat.BinData.new()
resp:get_body_bd(timestampReply)

-- Convert the binary timestamp reply to XML
local asn = chilkat.Asn.new()
success = asn:load_bd(timestampReply)
if not success then
    print(asn.last_error_text)
    return
end

local xml = chilkat.Xml.new()
success = xml:load_xml(asn:asn_to_xml())

-- 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  }

local tstInfoBase64 = xml:get_child_content("sequence[1]|contextSpecific|sequence|sequence|contextSpecific|octets")

local bdTstInfo = chilkat.BinData.new()
bdTstInfo:append_encoded(tstInfoBase64, "base64")

local asnTstInfo = chilkat.Asn.new()
success = asnTstInfo:load_bd(bdTstInfo)
if not success then
    print(asnTstInfo.last_error_text)
    return
end

local xmlTstInfo = chilkat.Xml.new()
success = xmlTstInfo:load_xml(asnTstInfo:asn_to_xml())
print(xmlTstInfo:get_xml())

-- 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

local sbGenTime = chilkat.StringBuilder.new()
sbGenTime:decode_and_append(xmlTstInfo:get_child_content("universal"), "base64", "utf-8")
print(sbGenTime:get_as_string())

-- Result:
-- 20230316115718Z