---> **`CT Deployment
Study <https://theno.github.io/presi-ct-deployment>`__** <---

--------------

ctutlz
======

Python utils library and tools for `Certificate
Transparency <https://www.certificate-transparency.org/>`__.

|Build Status| |Supported Python Versions| |PyPI Version|

This is the first implementation in Python which scrapes the SCTs at the
TLS handshake by `certificate
extension <https://www.certificate-transparency.org/how-ct-works#TOC-X.509v3-Extension>`__,
by `TLS
extension <https://www.certificate-transparency.org/how-ct-works#TOC-TLS-Extension>`__,
and by `OCSP
stapling <https://www.certificate-transparency.org/how-ct-works#TOC-OCSP-Stapling>`__
directly using the OpenSSL C-API (without forking subprocesses to call
any OpenSSL commands).

+-------------------------------------------+
| \* `Usage <#usage>`__                     |
+-------------------------------------------+
| \* `verify-scts <#verify-scts>`__         |
+-------------------------------------------+
| \* `ctloglist <#ctloglist>`__             |
+-------------------------------------------+
| \* `decompose-cert <#decompose-cert>`__   |
+-------------------------------------------+
| \* `API <#api>`__                         |
+-------------------------------------------+
| \* `Installation <#installation>`__       |
+-------------------------------------------+
| \* `Development <#development>`__         |
+-------------------------------------------+
| \* `Fabfile <#fabfile>`__                 |
+-------------------------------------------+
| \* `Devel-Commands <#devel-commands>`__   |
+-------------------------------------------+

Usage
-----

verify-scts
~~~~~~~~~~~

::

    > verify-scts --help

    usage: verify-scts [-h] [--short | --debug]
                       [--cert-only | --tls-only | --ocsp-only]
                       [--log-list <filename> | --latest-logs]
                       hostname [hostname ...]

    Verify Signed Certificate Timestamps (SCTs) delivered from one or several
    hosts by X.509v3 extension, TLS extension, or OCSP stapling

    positional arguments:
      hostname              host name of the server (example: 'ritter.vg')

    optional arguments:
      -h, --help            show this help message and exit
      --short               show short results and warnings/errors only
      --debug               show more for diagnostic purposes
      --cert-only           only verify SCTs included in the certificate
      --tls-only            only verify SCTs gathered from TLS handshake
      --ocsp-only           only verify SCTs gathered via OCSP request
      --log-list <filename>
                            filename of a log list in JSON format
      --latest-logs         for SCT verification against known CT Logs (compliant
                            with Chrome's CT policy) download latest version of
                            https://www.certificate-transparency.org/known-
                            logs/all_logs_list.json -- use built-in log list
                            really_all_logs.json from 2017-08-11 if --latest-logs
                            or --log-list are not set

Examples:

::

    > verify-scts google.com --short

    # google.com

    ## SCTs by Certificate

    no SCTs

    ## SCTs by TLS

    ```
    LogID b64 : pLkJkLQYWBSHuxOizGdwCjw1mAT5G9+443fNDsgN3BA=
    Sign. b64 : MEUCIGUHno90gGUepkOAkIWf0js56ce7FVnq1sXRM+cW8xdzAiEAzTRcHqxnBTTBceBlniPpc8OmyxJQLK6nQY8VW3bUsZk=
    Log found : Google 'Pilot' log
    Result    : Verified OK
    ```

    ```
    LogID b64 : 3esdK3oNT6Ygi4GtgWhwfi6OnQHVXIiNPRHEzbbsvsw=
    Sign. b64 : MEYCIQDpSgD3XhIQfqmO0IpHIJma/lchgYbT5yLjlVUYDBOspAIhAOjiHIhceJn0zxrfaT36HMDyY55IntNJ0Ur394NJnU8B
    Log found : Symantec log
    Result    : Verified OK
    ```

    ## SCTs by OCSP

    no SCTs

.. code:: bash

    > verify-scts  ritter.vg  sslanalyzer.comodoca.com  www.db.com
    #   has           ⇧                ⇧                  ⇧
    # scts by:   TLS-extension   OCSP-extension   certificate (precert)

.. code:: bash

    # nice: convert the markdown formatted output into other formats with pandoc
    domain=ritter.vg
    fmt=pdf  # {pdf,html,rst,...}
    verify-scts $domain 2>&1 | pandoc --from=markdown -o $domain-scts.$fmt

ctloglist
~~~~~~~~~

::

    > ctloglist --help

    usage: ctloglist [-h] [-v] [--short | --debug] [--json | --schema]

    Download, merge and summarize known logs for Certificate Transparency (CT)

    optional arguments:
      -h, --help     show this help message and exit
      -v, --version  print version number
      --short        show short results
      --debug        show more for diagnostic purposes
      --json         print merged log lists as json
      --schema       print json schema

    Print output to stdout, warning and errors to stderr. Currently there exist
    three log lists with differing infos: 1. listing of webpage
    https://www.certificate-transparency.org/known-logs 2. log_list.json 3.
    all_logs_list.json. This three log lists will be merged into one list in the
    future.

| Discussion:
| https://groups.google.com/forum/?fromgroups#!topic/certificate-transparency/zBv7EK0522w

Created with ``ctloglist``: \*
`really\_all\_logs.md <https://github.com/theno/ctutlz/blob/master/ctutlz/really_all_logs.md>`__
\*
`really\_all\_logs.json <https://github.com/theno/ctutlz/blob/master/ctutlz/really_all_logs.json>`__

Examples:

.. code:: bash

    # list really all known logs
    #  infos aggregated from:
    #  * log_list.json
    #  * all_logs.json
    #  * from log list webpage

    # overview
    > ctloglist --short

    # full, aggregated info
    > ctloglist

    # write into a json file
    > ctloglist --json > really_all_logs.json

.. code:: bash

    # only show inconsistencies of the ct log lists
    > ctloglist 1>/dev/null

decompose-cert
~~~~~~~~~~~~~~

::

    > decompose-cert --help

    usage: decompose-cert [-h] [-v] --cert <filename> [--tbscert <filename>]
                          [--sign-algo <filename>] [--signature <filename>]

    Decompose an ASN.1 certificate into its components tbsCertificate in DER
    format, signatureAlgorithm in DER format, and signatureValue as bytes
    according to https://tools.ietf.org/html/rfc5280#section-4.1

    optional arguments:
      -h, --help            show this help message and exit
      -v, --version         print version number
      --tbscert <filename>  write extracted tbsCertificate to this file (DER
                            encoded)
      --sign-algo <filename>
                            write extracted signatureAlgorithm to this file (DER
                            encoded)
      --signature <filename>
                            write extracted signatureValue to this file

    required arguments:
      --cert <filename>     Certificate in PEM, Base64, or DER format

API
~~~

Import module in your python code, for example:

.. code:: python

    > python3.6

    >>> from ctutlz.ctlog import download_log_list
    >>> from ctutlz.scripts.verify_scts import verify_scts_by_tls
    >>> from ctutlz.tls.handshake import do_handshake
    >>>
    >>> ctlogs = download_log_list()
    >>> handshake_res = do_handshake('google.com')
    >>> verifications = verify_scts_by_tls(handshake_res, ctlogs)
    >>> for ver in verifications:
    ...   print(f'{ver.verified}: {ver.log.description}')
    ...
    True: Google 'Pilot' log
    True: Symantec log
    >>>
    >>> from ctutlz.rfc6962 import SignedCertificateTimestamp, MerkleTreeLeaf

Installation
------------

Install the latest version of the pypi python package
`ctutlz <https://pypi.python.org/pypi/ctutlz>`__:

.. code:: bash

    pip install ctutlz

Development
-----------

Clone the source code `repository <https://github.com/theno/ctutlz>`__:

::

    git clone https://github.com/theno/ctutlz.git
    cd ctutlz

Fabfile
~~~~~~~

The ``fabfile.py`` contains devel-tasks to be executed with
`Fabric <http://www.fabfile.org/>`__ (maybe you need to
`install <http://www.fabfile.org/installing.html>`__ it):

::

    > fab -l

    Available commands:

        clean    Delete temporary files not under version control.
        pypi     Build package and upload to pypi.
        pythons  Install latest pythons with pyenv.
        test     Run unit tests.
        tox      Run tox.

    # Show task details, e.g. for task `test`:
    > fab -d test

    Run unit tests.

        Keyword-Args:
            args: Optional arguments passed to pytest
            py: python version to run the tests against

        Example:

            fab test:args=-s,py=py27

At first, set up python versions with
`pyenv <https://github.com/pyenv/pyenv>`__ and virtualenvs for
development with `tox <https://tox.readthedocs.io/en/latest/>`__:

::

    fab pythons
    fab tox

Tox creates virtualenvs of different Python versions (if they not exist
already) and runs the unit tests against each virtualenv.

On Ubuntu 16.04 you must install ``libpython-dev`` and
``libpython3-dev`` in order to make the tests passing for Python-2.7 and
Python-3.5:

.. code:: bash

    sudo apt-get install  libpython-dev  libpython3-dev

    # Then, rebuild the non-working Python-2.7 and Python-3.5 virtualenv and
    # run the unit tests:
    fab tox:'-e py27 -e py35 --recreate'

Devel-Commands
~~~~~~~~~~~~~~

Run unit tests against several pythons with tox (needs pythons defined
in envlist of ``tox.ini`` to be installed with pyenv):

.. code:: bash

    python3.6 -m tox

    # only against one python version:
    python3.6 -m tox -e py27

    # rebuild virtual environments:
    python3.6 -m tox -r

Run unit tests with pytest (uses tox virtualenv, replace ``py36`` by
e.g. ``py27`` where applicable):

.. code:: bash

    PYTHONPATH='.' .tox/py36/bin/python -m pytest

    # show output
    PYTHONPATH='.' .tox/py36/bin/python -m pytest -s

Run tool ``verify-scts`` from source:

.. code:: bash

    PYTHONPATH='.' .tox/py36/bin/python  ctutlz/scripts/verify_scts.py -h

Update really\_all\_logs
~~~~~~~~~~~~~~~~~~~~~~~~

::

    .tox/py36/bin/ctloglist > ctutlz/really_all_logs.md
    .tox/py36/bin/ctloglist --json > ctutlz/really_all_logs.json

.. |Build Status| image:: https://travis-ci.org/theno/ctutlz.svg?branch=master
   :target: https://travis-ci.org/theno/ctutlz
.. |Supported Python Versions| image:: https://img.shields.io/pypi/pyversions/ctutlz.svg
   :target: https://pypi.python.org/pypi/ctutlz
.. |PyPI Version| image:: https://img.shields.io/pypi/v/ctutlz.svg
   :target: https://pypi.python.org/pypi/ctutlz
