A simple client library for cryptographic timestamping service implementing the protocol from RFC3161. Based on python-rfc3161 with some additional fixes.
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README.rst

rfc3161ng

Build Status Latest PyPI version Supports Wheel format

A simple client library for cryptographic timestamping service implementing the protocol from RFC3161.

This started as a fork of https://dev.entrouvert.org/projects/python-rfc3161 and has some additional patches such as Python3 support.

The latest version of this library is available from https://github.com/trbs/rfc3161ng/ .

Public providers

There are several timestamping services around. Here is a list of publicly available services you can try:

Example

>>> import rfc3161ng
>>> certificate = open('data/certum_certificate.crt', 'rb').read()
>>> rt = rfc3161ng.RemoteTimestamper('http://time.certum.pl', certificate=certificate)
>>> tst = rt.timestamp(data=b'John Doe')
>>> rt.check(tst, data=b'John Doe')
True
>>> rfc3161ng.get_timestamp(tst)
datetime.datetime(2017, 8, 31, 15, 42, 58, tzinfo=tzutc())

Verifying timestamp using OpenSSL

One can verify the timestamp returned by the timeserver by using OpenSSL. For example with:

$ openssl ts -verify -data data_file.txt -in data_file.tsr -CAfile cacert.pem -untrusted tsa.crt

To save the tsr you can use code similar to:

>>> from pyasn1.codec.der import encoder
>>> import rfc3161ng
>>> ...
>>> timestamper = rfc3161ng.RemoteTimestamper('http://freetsa.org/tsr', certificate=certificate_data)
>>> tsr = timestamper(data=data_file.read(), return_tsr=True)
>>> with open("data_file.tsr", "wb") as f:
>>>     f.write(encoder.encode(tsr))

Alternatively you can just save the raw response.content returned from the certification server.

There is a test which also covers this in test_verify_timestamp_response_with_openssl.

Authors