RSA Encryption/Decryption in Python and Nodejs

crypto.js

const crypto = require('crypto');

var { publicKey, privateKey } = crypto.generateKeyPairSync('rsa', {
    modulusLength: 4096,
    publicKeyEncoding: {
        type: 'spki',
        format: 'pem'
    }
});


function encryptString (data, publicKey) {
    // data: text string to be encrypted
    // publicKey: Crypto Object or PEM

    const encrypted = crypto.publicEncrypt(
        {
            key: publicKey,
            padding: crypto.constants.RSA_PKCS1_OAEP_PADDING,
            oaepHash: "sha256",
        },
        Buffer.from(data)
    )

    // Return: Base64 encoded encrypted text
    return encrypted.toString("base64");
}


function decryptString (data, privateKey) {
    // data: base64 encoded encrypted text
    // privateKey: Crypto Object or PEM

    const decrypted = crypto.privateDecrypt(
        {
            key: privateKey,
            padding: crypto.constants.RSA_PKCS1_OAEP_PADDING,
            oaepHash: "sha256",
        },
        Buffer.from(data, 'base64')
    )

    // Return: plain text message
    return decrypted.toString()
}

crypto.py

from typing import Tuple

from Crypto import Random
from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
from Crypto.PublicKey.RSA import RsaKey


def newkeys(keysize: int) -> Tuple[RsaKey, RsaKey]:
    random_generator = Random.new().read
    key = RSA.generate(keysize, random_generator)
    private, public = key, key.publickey()
    return public, private


def encrypt(message: bytes, pub_key: RsaKey):
    cipher = PKCS1_OAEP.new(pub_key)
    return cipher.encrypt(message)


def decrypt(ciphertext: bytes, priv_key: RsaKey):
    cipher = PKCS1_OAEP.new(priv_key)
    return cipher.decrypt(ciphertext)