Recently at work, I was tasked to write a Java program which would encrypt a sensitive string using the RSA encryption algorithm. The encrypted string would then be passed on to a client over public internet. The client would then use the private key to decrypt the message. But the client is written in Python. So I have to make sure the encryption and decryption wok as expected. And as always, I wrote POCs for both. And here, I'm going to document that. Creating the key pair Before we can start the encryption, we need to have a key pair. A key pair will have a public key and a private key. The public key, as the name suggests, is public. You