CkPython

RFC3161 Timestamp Client - Fetch from Timestamp Authority (TSA) and Verify

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Sends an RFC 3161 timestamp request to a TSA (Timestamp Authority) server and validates the timestamp token response. CkPython

import sys
import chilkat

success = False

# 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 = chilkat.CkCrypt2()
crypt.put_HashAlgorithm("sha256")
crypt.put_EncodingMode("base64")
base64Hash = crypt.hashStringENC("Hello World")

http = chilkat.CkHttp()

requestToken = chilkat.CkBinData()
optionalPolicyOid = ""
addNonce = False
requestTsaCert = True

# Create a time-stamp request token
success = http.CreateTimestampRequest("sha256",base64Hash,optionalPolicyOid,addNonce,requestTsaCert,requestToken)
if (success == False):
    print(http.lastErrorText())
    sys.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' https://freetsa.org/tsr > file.tsr
tsaUrl = "https://freetsa.org/tsr"
# Another timestamp server you could try is: http://timestamp.digicert.com
tsaUrl = "http://timestamp.digicert.com"
resp = chilkat.CkHttpResponse()
success = http.HttpBd("POST",tsaUrl,requestToken,"application/timestamp-query",resp)
if (success == False):
    print(http.lastErrorText())
    sys.exit()

# Get the timestamp reply from the HTTP response object.
timestampReply = chilkat.CkBinData()
resp.GetBodyBd(timestampReply)

# Show the base64 encoded timestamp reply.
print(timestampReply.getEncoded("base64"))

# Let's verify the timestamp reply against the TSA's cert, which we've previously downloaded.
# See https://freetsa.org/index_en.php
tsaCert = chilkat.CkCert()
success = tsaCert.LoadFromFile("qa_data/certs/freetsa.org.cer")
if (success == False):
    print(tsaCert.lastErrorText())
    sys.exit()

# The VerifyTimestampReply method will return one of the following values:
# -1:  The timestampReply does not contain a valid timestamp reply.
# -2: The  timestampReply is a valid timestamp reply, but failed verification using the public key of the tsaCert.
# 0:  Granted and verified.
# 1: Granted and verified, with mods (see RFC 3161)
# 2: Rejected.
# 3: Waiting.
# 4: Revocation Warning
# 5: Revocation Notification
pkiStatus = http.VerifyTimestampReply(timestampReply,tsaCert)
if (pkiStatus < 0):
    print(http.lastErrorText())
    sys.exit()

print("pkiStatus = " + str(pkiStatus))

json = chilkat.CkJsonObject()
http.GetLastJsonData(json)

json.put_EmitCompact(False)
print(json.emit())

# The JSON looks like the following.

# Use this online tool to generate parsing code from sample JSON: 
# Generate Parsing Code from JSON

# {
#   "timestampReply": {
#     "pkiStatus": {
#       "value": 0,
#       "meaning": "granted"
#     }
#   },
#   "pkcs7": {
#     "verify": {
#       "digestAlgorithms": [
#         "sha256"
#       ],
#       "signerInfo": [
#         {
#           "cert": {
#             "serialNumber": "04CD3F8568AE76C61BB0FE7160CCA76D",
#             "issuerCN": "DigiCert SHA2 Assured ID Timestamping CA",
#             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
#             "digestAlgName": "SHA256"
#           },
#           "contentType": "1.2.840.113549.1.9.16.1.4",
#           "signingTime": "200405023019Z",
#           "messageDigest": "f14zOsdnN9vyyV3HjjBiLzNDi1PF28hAFMODxNkNRZs=",
#           "signingAlgOid": "1.2.840.113549.1.1.1",
#           "signingAlgName": "RSA-PKCSV-1_5",
#           "authAttr": {
#             "1.2.840.113549.1.9.3": {
#               "name": "contentType",
#               "oid": "1.2.840.113549.1.9.16.1.4"
#             },
#             "1.2.840.113549.1.9.5": {
#               "name": "signingTime",
#               "utctime": "200405023019Z"
#             },
#             "1.2.840.113549.1.9.16.2.12": {
#               "name": "signingCertificate",
#               "der": "MBowGDAWBBQDJb1QXtqWMC3CL0+gHkwovig0xQ=="
#             },
#             "1.2.840.113549.1.9.4": {
#               "name": "messageDigest",
#               "digest": "f14zOsdnN9vyyV3HjjBiLzNDi1PF28hAFMODxNkNRZs="
#             }
#           }
#         }
#       ]
#     }
#   }
# }

signingTime = chilkat.CkDtObj()
authAttrSigningTimeUtctime = chilkat.CkDtObj()

timestampReplyPkiStatusValue = json.IntOf("timestampReply.pkiStatus.value")
timestampReplyPkiStatusMeaning = json.stringOf("timestampReply.pkiStatus.meaning")
i = 0
count_i = json.SizeOfArray("pkcs7.verify.digestAlgorithms")
while i < count_i :
    json.put_I(i)
    strVal = json.stringOf("pkcs7.verify.digestAlgorithms[i]")
    i = i + 1

i = 0
count_i = json.SizeOfArray("pkcs7.verify.signerInfo")
while i < count_i :
    json.put_I(i)
    certSerialNumber = json.stringOf("pkcs7.verify.signerInfo[i].cert.serialNumber")
    certIssuerCN = json.stringOf("pkcs7.verify.signerInfo[i].cert.issuerCN")
    certDigestAlgOid = json.stringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid")
    certDigestAlgName = json.stringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName")
    contentType = json.stringOf("pkcs7.verify.signerInfo[i].contentType")
    json.DtOf("pkcs7.verify.signerInfo[i].signingTime",False,signingTime)
    messageDigest = json.stringOf("pkcs7.verify.signerInfo[i].messageDigest")
    signingAlgOid = json.stringOf("pkcs7.verify.signerInfo[i].signingAlgOid")
    signingAlgName = json.stringOf("pkcs7.verify.signerInfo[i].signingAlgName")
    authAttrContentTypeName = json.stringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".name")
    authAttrContentTypeOid = json.stringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".oid")
    authAttrSigningTimeName = json.stringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.5\".name")
    json.DtOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.5\".utctime",False,authAttrSigningTimeUtctime)
    authAttrSigningCertificateName = json.stringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.16.2.12\".name")
    authAttrSigningCertificateDer = json.stringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.16.2.12\".der")
    authAttrMessageDigestName = json.stringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".name")
    authAttrMessageDigestDigest = json.stringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".digest")
    i = i + 1