CkPython

Combine Timestamp Reply and Content File into a TimeStampData

See more ASN.1 Examples

Demonstrates how to combine a timestamp reply (RFC 3161) with a data file (any type of file) to create a TimeStampData structure (RFC 5544). CkPython

import sys
import chilkat

success = False

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# Also see this example:
# Send a TimeStamp Request to a TimeStamp Authority and get the Response

# Load a timestamp reply file
bdTsr = chilkat.CkBinData()
success = bdTsr.LoadFile("qa_data/tsd/sample.tsr")
if (success != True):
    print("Failed to load timestamp reply file.")
    sys.exit()

# Load the tsr into an ASN.1 object.
asnTsr = chilkat.CkAsn()
success = asnTsr.LoadEncoded(bdTsr.getEncoded("base64"),"base64")
if (success != True):
    print(asnTsr.lastErrorText())
    sys.exit()

# Get the timestamp reply as XML.
xmlTsr = chilkat.CkXml()
xmlTsr.LoadXml(asnTsr.asnToXml())

# The timestamp reply XML begins like this:
# We'll want to remove the 1st "sequence" subtree.

#     <?xml version="1.0" encoding="utf-8"?>
#     <sequence>
#         <sequence>       <---- Remove this sub-tree.
#             <int>00</int>
#             <sequence>
#                 <utf8>Operation Okay</utf8>
#             </sequence>
#         </sequence>
#         <sequence>   
#             <oid>1.2.840.113549.1.7.2</oid>
#             <contextSpecific tag="0" constructed="1">
#             ...

# Remove the 1st sub-tree..
xmlTsr.RemoveChildByIndex(0)

# In this example, the data file we're combining with the timestamp into a timestampData is a .p7m.
# However, it can be any type of file (text or binary), it doesn't matter..
bdContent = chilkat.CkBinData()
success = bdContent.LoadFile("qa_data/tsd/sample.p7m")
if (success != True):
    print("Failed to load content file.")
    sys.exit()

# Begin building the TimeStampData.  
# We'll build as XML and then convert to ASN.1
xml = chilkat.CkXml()
xml.put_Tag("sequence")
xml.UpdateChildContent("oid","1.2.840.113549.1.9.16.1.31")
xml.UpdateAttrAt("contextSpecific",True,"tag","0")
xml.UpdateAttrAt("contextSpecific",True,"constructed","1")
xml.UpdateChildContent("contextSpecific|sequence|int","01")
xml.UpdateChildContent("contextSpecific|sequence|octets",bdContent.getEncoded("base64"))
xml.UpdateAttrAt("contextSpecific|sequence|contextSpecific",True,"tag","0")
xml.UpdateAttrAt("contextSpecific|sequence|contextSpecific",True,"constructed","1")

# xContext is a CkXml
xContext = xml.GetChildWithTag("contextSpecific|sequence|contextSpecific")
xContext.AddChildTree(xmlTsr)

# Convert the XML to ASN.1
tsd = chilkat.CkAsn()
tsd.LoadAsnXml(xml.getXml())

# Write the timestamped data to a file.
success = tsd.WriteBinaryDer("qa_output/sample.tsd")

# Alternatively, get the tsd ASN.1 as base64..
tsdBase64 = tsd.getEncodedDer("base64_mime")
print(tsdBase64)