Added/Blockchain RSA Algorithm

[SportingDot1024]

Describe your change:

I have successfully incorporated RSA encryption and decryption into my project using the cryptography library, a Python package. As you may know, RSA is an algorithm that employs private and public keys for data transmission. By leveraging this library, I was able to streamline the processes of generation and encryption/decryption, thereby significantly enhancing data security.

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

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 include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE_NUMBER".

[algorithms-keeper]

Click here to look at the relevant links ⬇️

🔗 Relevant Links

Repository:

• Contributing guidelines
• Project Euler solution guidelines

Python:

• Formatted string literals (f-strings)
• Type hints
• doctest
• unittest
• pytest

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[algorithms-keeper]

Please provide return type hint for the function: generate_key_pair. If the function does not return a value, please provide the type hint as: def function() -> None:

[SportingDot1024]

done

[algorithms-keeper]

Please provide return type hint for the function: encrypt. If the function does not return a value, please provide the type hint as: def function() -> None:

Please provide type hint for the parameter: message

Please provide type hint for the parameter: public_key

[SportingDot1024]

done

[tianyizheng02]

1. We already have an implementation of RSA in ciphers/rsa_cipher.py. If you wish to contribute, please do the due diligence of checking the codebase to see if an algorithm is already implemented.
2. This file is a how-to demonstration of the cryptography library. You did not implement the RSA algorithm yourself.

   from cryptography.hazmat.backends import default_backend
   from cryptography.hazmat.primitives import hashes
   from cryptography.hazmat.primitives.asymmetric import padding, rsa