In Python, there are many libraries using which one can perform RSA key generation, encryption, and decryption. Python rsa module is one such example. But, in this article, we would discuss how to generate RSA keys without using any cryptographic libraries. We would use modules like secrets and math and use those to generate RSA keys using which we can perform RSA encryption and decryption.

Firstly, let’s see how to generate RSA keys using a cryptographic module. We would use the rsa module for this purpose.

import rsa

KEY_LENGTH = 2048
publickey, privatekey = rsa.newkeys(KEY_LENGTH)

plaintext = "Secret"

ciphertext = rsa.encrypt(plaintext.encode(), publickey)

decrypted_text = rsa.decrypt(ciphertext, privatekey).decode()
print(decrypted_text)

The above program generates RSA private and public keys. It then encrypts the test “Secret” using the public key. Later, it uses the private key to decrypt the encrypted ciphertext and gets the plaintext.

We have already discussed how the RSA cryptosystem works. We would generate two cryptographically secure random prime numbers and use the same algorithm to generate RSA private and public keys from the generated prime numbers.