Adafruit-circuitpython-rsa

We have upgraded Pylint checks to use the latest version of Pylint and implemented usage of Black Python formatting. This does not change the functionality of the code - it is designed to bring it up to current standards and make it more readable.

* Remove pinned Pylint version number from build.yml file
* Synced `.pylintrc` file to match Adafruit standard
* Ran upgraded Pylint and applied any changes or new disables necessary
* Ran Black formatter and allowed application of changes across entire repo

For more information on using Pylint and Black on your code, check out [this guide on working with Pylint and Black](https://learn.adafruit.com/improve-your-code-with-pylint)

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-rsa`.

Read the [docs](http://circuitpython.readthedocs.io/projects/rsa/en/latest/) for info on how to use it.

This release includes:
* Migrating this repository from Travis to GitHub Actions. This has no effect on the behavior of the code itself.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

Read the [docs](http://circuitpython.readthedocs.io/projects/rsa/en/latest/) for info on how to use it.

* Adds appropriate `__version__` and `__repo__` strings to `adafruit_rsa/*.py` files for CircuitPython consistency.

* `__version__` string reflecting the [python-rsa](https://github.com/sybrenstuvel/python-rsa) version in `__init__.py` commented out.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

Read the [docs](http://circuitpython.readthedocs.io/projects/rsa/en/latest/) for info on how to use it.

Fixes extra-zero-append error within `transform.py`/`int2bytes` causing invalid RSA signatures.

Adds `util/` folder with script to run on your computer (_not_ the CircuitPython device) to generate public (`rsa_public.pem`) and private(`rsa_private.pem`) key pairs. The script also decodes the generated `rsa_private.pem` into a `PrivateKey` tuple for copy/paste into a `secrets.py` dict. file on a CircuitPython board.


To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

Read the [docs](http://circuitpython.readthedocs.io/projects/rsa/en/latest/) for info on how to use it.

CircuitPython_RSA` is a port of [Python-RSA, a pure-Python RSA implementation](https://github.com/sybrenstuvel/python-rsa) to CircuitPython.

**Modifications from Python-RSA**
* Command-line-specific tools have been removed from the library to save space.
* CPython Logging has been replaced with the Adafruit CircuitPython Logger Module.
* Miller–Rabin Primality test algorithm modified to support library's `fast_pow`, CircuitPython's `pow()` does not support modular exponentiation.
* CPython `binascii` and `hashlib` modules replaced with `Adafruit_CircuitPython_binascii` and `Adafruit_CircuitPython_hashlib`

**Support for:**
* RSA Key pair (private/public) generation
* Message encryption and decryption
* Signature creation and verification
* w/SHA-256, SHA-384, SHA-512 (using `Adafruit_CircuitPython_hashlib`, pure-python implementation. SHA-1 and MD5 are currently unsupported.)

Examples are provided for signature creation/verification, keypair generation and encryption/decryption, and a unit-test-like for testing future modifications to this library.


To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

Read the [docs](http://circuitpython.readthedocs.io/projects/rsa/en/latest/) for info on how to use it.