With this, your messages can't be monitored

I think everyone should learn to use RSA, Because only in the encrypted world , Our privacy can be truly protected . Today, let's share how to use Python To apply RSA.

Let's start with a scene , You are a A, Send an important message to B, But through any chat APP It's not safe , May be monitored , It may also be recorded , So you need to encrypt the message .

How to encrypt security , That's using RSA Public key encryption , Private key decryption , The public key can be made public , Private key is not public .

First step : Key generation and public key exchange

First pip install rsa

A Make a pair of RSA secret key , It's called public key A, Private key A

from rsa import newkeys
public_key_a, private_key_a = newkeys(2048, poolsize=8)
with open("public_key_a.pem", "wb") as f:
    f.write(public_key_a.save_pkcs1(format="PEM"))
with open("private_key_a.pem", "wb") as f:
    f.write(private_key_a.save_pkcs1(format="PEM"))

public_key_a.pem Is as follows ：

-----BEGIN RSA PUBLIC KEY-----
MIIBCgKCAQEArAdHKqjnVzeMt+4DpmQvoQsaKokL05+DS6Kykj1KiOmVWLreIUfP
fvedIRykBFNODwHQHGtWGPeaMYs86+9zdIRMtqC0TlXQyj74aP9CTAV43SSA65kY
EwQVJh3QBmrQok8lEljhN/QbiWrw4xG+rYP6BgsHFM3tuHb6oIkuhL6r+A3hj2ep
DY3jxn0ZPNSN10i9tTC/KXqKGnJrOAEQ6nNL/mAnFLwiuDQrEBmXfnK5bpw7hjDy
pJ0Cs3JM74+OTxo76Tbay1nWGGipLSXzRCXQW2+AD4Q6bFq6nuGic9gQLvQa11B7
XZVhVvVTxrezAOMYL3FOFXfIFqOB8HvTEQIDAQAB
-----END RSA PUBLIC KEY-----

B Make a pair of RSA secret key , It's called public key B, Private key B.

from rsa import newkeys
public_key_b, private_key_b = newkeys(2048, poolsize=8)
with open("public_key_b.pem", "wb") as f:
    f.write(public_key_b.save_pkcs1(format="PEM"))
with open("private_key_b.pem", "wb") as f:
    f.write(private_key_b.save_pkcs1(format="PEM"))

A The file public_key_a.pem Send to B,B Also put public_key_b.pem Send to A, This completes the exchange of keys . Back A Want to be with B signal communication , Just use B Public key encrypted message for ,B Decrypt with your own private key , You can get A Message sent , vice versa .

The second step : encryption

for instance A There is now a B The public key , When you want to encrypt messages , Load... First B The public key ：

import base64
from rsa import PublicKey, PrivateKey, encrypt, decrypt,

public_key_b_file = Path("./public_key_b.pem")
public_key_b = PublicKey.load_pkcs1(public_key_b_file.read_bytes(), format="PEM")
print(public_key_b)

You can get this output

PublicKey(21831899084185660921840174683452830587321319689015722246782364711292417600371532112177905506057539367671580668438126704427894857192387484162751992715040787885971624030995019473104987454304337735143558728644817397903950824366991556950207676816787133824709081376405184001095218083813620277536858163575686850410455092011765877504499366336792653732470469604531683754075419135479867324338689671063858801578735120084016574895760616498188773853425143006311923355945139917528996017456427975883103933944819388497917519791324247040364723098266886847457872058619189743684510784904551008906591879274280765194272666652349889346853, 65537)

Then put the plaintext first according to utf-8 Encoded in bytes , In encryption , And then go base64, You can send it to B 了 .

import base64
from rsa import PublicKey, PrivateKey, encrypt, decrypt

if __name__ == "__main__":
    public_key_b_file = Path("./public_key_b.pem")
    public_key_b = PublicKey.load_pkcs1(public_key_b_file.read_bytes(), format="PEM")
    # print(public_key_b)
    orgin_message = " The withdrawal password is  123321"
    encrypt_message = base64.b64encode(
        encrypt(orgin_message.encode("utf-8"), public_key_b)
    )
    print(encrypt_message.decode())

The ciphertext is ：

mlVecdANZxsvXPivECRvNpoJr+2NxElM84moDr5N3FoKdxvubcHcteA4AW7UyHMj2PD96jaiQiD6hWX6M4dFePi05IE6k6JdAVXWSq5fTbZsiqBggidrcDL3azAaW5e4jQ6md6Bem1XcVAo2u1meIl+rXPKLUECu9R4tkgjtUTgUZpZ7rObl18Sz51A86ZxxRIEwkmG+TYJUPa27CyMPgD0zqlrKqh4SjIRZ1e3SmWxyet+3XFLE2b1XJwMhPUOFsJEO6qs204WtvpOYH0nGQorYsJe+ReIx/W0zZyK4zE+En9xW7fBByYNrseonh3sm6ALG6cRpZV/Odd2vmRUtOQ==

And every time the same plaintext is encrypted into ciphertext, the result is different , Brute force cracking is almost impossible ：

The second step : Decrypt

Decryption is to decrypt with your own key , Also load your private key first , And public_key_b It's a pair. .

import base64
from rsa import PublicKey, PrivateKey, encrypt, decrypt

if __name__ == "__main__":

    encrypted_msg = "mlVecdANZxsvXPivECRvNpoJr+2NxElM84moDr5N3FoKdxvubcHcteA4AW7UyHMj2PD96jaiQiD6hWX6M4dFePi05IE6k6JdAVXWSq5fTbZsiqBggidrcDL3azAaW5e4jQ6md6Bem1XcVAo2u1meIl+rXPKLUECu9R4tkgjtUTgUZpZ7rObl18Sz51A86ZxxRIEwkmG+TYJUPa27CyMPgD0zqlrKqh4SjIRZ1e3SmWxyet+3XFLE2b1XJwMhPUOFsJEO6qs204WtvpOYH0nGQorYsJe+ReIx/W0zZyK4zE+En9xW7fBByYNrseonh3sm6ALG6cRpZV/Odd2vmRUtOQ=="
    private_key_b_file = Path("./private_key_b.pem")
    private_key_b = PrivateKey.load_pkcs1(private_key_b_file.read_bytes(), format="PEM")
    origin_message = decrypt(base64.b64decode(encrypted_msg.encode()), private_key_b)
    print(origin_message.decode("utf-8"))
    #  The withdrawal password is  123321

as long as B The private key of has not been leaked , That's all B To unlock this ciphertext , So it's very safe .

Last words

In this article, we share our experience in Python How to use RSA encryption , You can make a communication program with encryption based on this , I hope it helped you .

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