== python-yubihsm

Python library and tests for the YubiHSM 2.
This library is compatible with both Python 2 and 3.

This library communicates with the YubiHSM 2 connector daemon, which must already be running.
It can also communicate directly with the YubiHSM 2 via USB.

=== License

....
Copyright 2018 Yubico AB

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
....

=== Installation

From PyPI:

 $ pip install yubihsm[http,usb]

From a source .tar.gz:

 $ pip install yubihsm-<version>.tar.gz[http,usb]


Omitting a tag from the brackets will install the library without support for
that backend, and will avoid installing unneeded dependencies.

=== Quick reference commands:
[source,python]
----
from yubihsm import YubiHsm
from yubihsm.defs import CAPABILITY, ALGORITHM
from yubihsm.objects import AsymmetricKey

# Connect to the YubiHSM via the connector using the default password:
hsm = YubiHsm.connect('http://localhost:12345')
session = hsm.create_session_derived(1, 'password')

# Generate a private key on the YubiHSM for creating signatures:
key = AsymmetricKey.generate(  # Generate a new key object in the YubiHSM.
    session,                   # Secure YubiHsm session to use.
    0,                         # Object ID, 0 to get one assigned.
    'My key',                  # Label for the object.
    1,                         # Domain(s) for the object.
    CAPABILITY.SIGN_ECDSA,     # Capabilities for the object.
    ALGORITHM.EC_P256          # Algorithm for the key.
)

# pub_key is a cryptography.io ec.PublicKey, see https://cryptography.io
pub_key = key.get_public_key()

# Write the public key to a file:
with open('public_key.pem', 'w') as f:
    f.write(pub_key.public_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PublicFormat.SubjectPublicKeyInfo
    ))

# Sign some data:
signature = key.sign_ecdsa(b'Hello world!')  # Create a signature.

# Clean up
session.close()
hsm.close()
----

=== Development
For development of the library, we recommend using `pipenv`. To set up the dev
environment, run this command in the root directory of the repository:

 $ pipenv install --dev

==== Running tests
Running the tests require a YubiHSM2 to run against, with the default
authentication key set.

WARNING: The YubiHSM under test will be factory reset by the tests!

 $ pipenv run test

You can specify a specific module or test to run by using the -s flag:

 $ pipenv run test -s test.device.test_ec

By default the tests will connect to a yubihsm-connector running with the
default settings on http://localhost:12345. To change this, use the `BACKEND`
variable, eg:

 $ BACKEND="yhusb://" pipenv run python setup.py test

Access to the device requires proper permissions, so either use sudo or setup a
udev rule.

==== Generating HTML documentation

To build the HTML documentation, run:

 $ pipenv run docs

The resulting output will be in docs/_build/html/.

==== Source releases for distribution
Build a source release:

 $ pipenv run python setup.py sdist

The resulting .tar.gz will be created in `dist/`.
