rsa-jpv

A simple Python library that encrypts your data using the RSA cryptosystem.

Installation

To install the library, open a terminal window and copy the command below.

$ pip install rsa-jpv

Note: Requires Python 3.6 or greater.

Quick Note

Don't use this library to encrypt data in a production environment. This version of RSA is not optimized for such use and may cause security issues which may lead to data loss or theft.

Documentation

Application Programming Interface

Link to API

Blog

Link to Blog

Example

Problem

Suppose that you and Bob are exchanging messages over an unencrypted communications channel. Bob informs you that he wants to send you a message that only the two of you should know. Since it's an unencrypted channel, anyone could tap into your communications and see your messages.

Solution

The RSA cryptosystem could help solve the problem described above by encrypting the messages sent by Bob to you.

Here's what you need to do:

  1. Generate a key pair (public key and private key)
  2. Keep the private key a secret (don't let anyone know except yourself)
  3. Send the public key to Bob (the public key can't be used to decrypt messages)
  4. Tell Bob to use the public key that you've given to encrypt his messages
  5. Decrypt the encrypted messages sent by Bob using your private key
Generating a Key Pair

Generating a key pair is as easy as calling the generate_key_pair() function.

>>> # Your code
>>> from rcj.cryptosystem import rsa
>>> key_pair = rsa.generate_key_pair()
>>> print(key_pair)
[PUBLIC KEY]
Key Contents:
Prime Product = 221147
Auxiliary = 11

[PRIVATE KEY]
Key Contents:
Prime Product = 221147
Auxiliary = 360131

The function returns an instance of type KeyPair and contains two attributes: public_key and private_key. As you could see from the example above, calling the print function on the KeyPair class reveals the content of the public_key and private_key.

At this point, you could already give Bob the public key by telling him the prime product and auxiliary under the public key section. Always remember to keep your private key a secret!

Encrypting Messages

Encrypting a message takes three steps:

  1. Creating an instance of the Key class by using the values of the public key

  2. Creating an instance of the Encryptor class by using the instance of the Key class we created in the first step

  3. Encrypting your message by using the encrypt() method of the Encryptor class

    Bob's code

    from rcj.cryptosystem import rsa
    public_key = rsa.Key(221147, 11)
    encryptor = rsa.Encryptor(public_key)
    encrypted_message = encryptor.encrypt("Let's go to the pub tonight.")
    print(encrypted_message)
    'ΰ‘Ύπ¨„˜π―’­π«¨¦π—“­πž’…π ΄ΰ¨›πž’…π―’­ΰ¨›πž’…π―’­π’‹Ώπ¨„˜πž’…π«΄’κ€Έπ΄‰›πž’…π―’­ΰ¨›π‹²π‘―­π ΄π’‹Ώπ―’­δ—†'

Creating an instance of the Key class takes two parameters: prime_product and auxiliary. Since we are encrypting in this case, the prime_product and auxiliary that we need to pass are those of the public key. Creating an instance of the Encryptor class takes a single parameter of type Key. In this case, you'll just pass the instance of the Key class with the values of the public key.

The encrypt() method of the Encryptor class takes in a string and returns the encrypted message.

Bob would need to follow the three steps described above to encrypt his message.

Decrypting Messages

Decrypting a message takes three steps:

  1. Creating an instance of the Key class by using the values of the private key

  2. Creating an instance of the Decryptor class by using the instance of the Key class we created in the first step

  3. Decrypting your message by using the decrypt() method of the Decryptor class

    Your code

    from rcj.cryptosystem import rsa
    private_key = rsa.Key(221147, 360131)
    decryptor = rsa.Decryptor(private_key)
    message = decryptor.decrypt("ΰ‘Ύπ¨„˜π―’­π«¨¦π—“­πž’…π ΄ΰ¨›πž’…π―’­ΰ¨›πž’…π―’­π’‹Ώπ¨„˜πž’…π«΄’κ€Έπ΄‰›πž’…π―’­ΰ¨›π‹²π‘―­π ΄π’‹Ώπ―’­δ—†")
    print(message)
    "Let's go to the pub tonight."


Written by Justine Paul Sanchez Vitan.

GitHub

https://github.com/jpvitan/rsa-jpv