Add content scramble system

[skimbleshank]

Describe your change:

Hi Python team! For Hacktoberfest, I resurrected an old algorithm I coded many years ago, and made it up to date with my current Python knowledge - The Content Scramble System (CSS). It may not meet all your standards, but I'm here to work with you to get it in the best shape possible!

One potential issue may be the doctests, the inputs and outputs to most functions are long binary arrays. I'm also happy to open a separate PR and transfer my write-ups to Algorithms-Explanation, since the algorithm is very technical in nature. There isn't much opportunity from my point of view to raise potential errors compared to some other cryptographic algorithms, since the algorithm works at the bit level.

I'm a data science developer for EdjAnalytics in Louisville KY and use Python daily. I'm always looking to improve the way I utilize Python and this seems like an excellent opportunity! Give my code a try by running:

$ python css.py

• Add an algorithm?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[TravisBuddy]

Travis tests have failed

Hey @summonholmes,
Please read the following log in order to understand the failure reason.
It'll be awesome if you fix what's wrong and commit the changes.

TravisBuddy Request Identifier: f92676c0-0985-11eb-b9d6-41d4da7e5060

[TravisBuddy]

Travis tests have failed

Hey @summonholmes,
Please read the following log in order to understand the failure reason.
It'll be awesome if you fix what's wrong and commit the changes.

TravisBuddy Request Identifier: 3e589430-09c2-11eb-b9d6-41d4da7e5060

[TravisBuddy]

Travis tests have failed

Hey @summonholmes,
Please read the following log in order to understand the failure reason.
It'll be awesome if you fix what's wrong and commit the changes.

TravisBuddy Request Identifier: c45b8650-09c2-11eb-b9d6-41d4da7e5060

[cozek]

Looks like a good project.
Rename css.py to content_scramble_system.py

I am not sure, but the pre-commit seems to be failing due to an unrelated file.
Run pre-commit locally and check
pre-commit run --verbose --all-files --show-diff-on-failure

[skimbleshank]

Looks like a good project.
Rename css.py to content_scramble_system.py

I am not sure, but the pre-commit seems to be failing due to an unrelated file.
Run pre-commit locally and check
pre-commit run --verbose --all-files --show-diff-on-failure

Strange, it did not fail this time when renaming css.py to content_scramble_system.py

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

Please reopen this pull request once you commit the changes requested or make improvements on the code. If this is not the case and you need some help, feel free to seek help from our Gitter or ping one of the reviewers. Thank you for your contributions!