Various Encryption Algorithms Implemented in Python

Encryption is generally about encrypting binary encoded formats, which corresponds to Python as Bytes. You need to convert str to Bytes using encode and decode.

import hashlib 

def MD5(str): 
    h1 =hashlib.md5() 
    h1.update(str.encode(encoding = 'utf-8')) 
    return h1.hexdigest()  # lowercase 

if __name__ == "__main__": 
    str ='123232' 
    md5 =MD5(str)
    print("Before encryption: "+ str)
    print("After encryption: " + md5)

Output:

Before encryption: 123232
After encryption: 552effa0980dcec34d29ca4ad27a11e0

import base64

def Ebase64(string):
    return str(base64.b64encode(string.encode("utf-8")),'utf-8')

if __name__ == '__main__':
    string = '123数据'
    print(f"{string}：{Ebase64(string)}")

Output:

123数据：MTIz5pWw5o2u

SHA1 encryption is more secure than MD5, but also slower.

a = "中国欢迎你".encode('utf-8') 
print(a) 

import hashlib 
b = hashlib.sha1(a).hexdigest() 
print(b)

Output:

b'\xe4\xb8\xad\xe5\x9b\xbd\xe6\xac\xa2\xe8\xbf\x8e\xe4\xbd\xa0'
1457a6057bfc0711a34595ec7a54c47fc4d7ab9f

(1) DES encryption

from Cryptodome.Cipher import DES 
import binascii 
# Key length 64 bits 
key = b'abcddesw'
def pad(text):
    # Encryption function, if text is not a multiple of 8, pad it
    while len(text) % 8 != 0:
        text += ' '
    return text
# Create DES instance 
des = DES.new(key,DES.MODE_ECB) 
text = "I'm china!"
padded_text = pad(text) 
print(padded_text) 
# Encrypt 
encrypted_text = des.encrypt(padded_text.encode("utf-8")) 
print(encrypted_text) 
# Decrypt, rstrip() returns a string with all characters removed from the end of the string 
plain_text = des.decrypt(encrypted_text).decode().rstrip(' ') 
print(plain_text)

Output:

I'm china!

b'\x04mp5.\xac\xd5\xa76M\xc6>s\x95F\xa4'I'm china!

(2) 3DES enhances the difficulty of brute force by extending the DES key length.

(3) AES encryption

from Cryptodome.Cipher import AES
from Cryptodome import Random
from binascii import  a2b_hex 

data = '南来北往'
# Key must be 16 (AES-128), 24, 32
key = b'this is a 16 key'
# Generate a non-repeating key vector equal to the AES block size
iv =Random.new().read(AES.block_size) 
print(iv) 
# Initialize AES object using key and Iv 
mycipher = AES.new(key,AES.MODE_CFB,iv) 
print(mycipher) 
cip = mycipher.encrypt(data.encode()) 
# Add iv to the beginning of the encrypted key 
ciptext =iv + cip 
print(ciptext) 
# Decrypt requires key and iv to generate AES object, first 16 bits are iv 
mydecrypt = AES.new(key,AES.MODE_CFB,ciptext[:16]) 
# Last 16 bits are the key 
decrytext = mydecrypt.decrypt(ciptext[16:]) 
print(decrytext.decode())

Output:

b'"I\xa8e\xd0\x95MK>\xe7+\x07'\xde\xe2\x13'
<Cryptodome.Cipher._mode_cfb.CfbMode object at 0x000000000291B8D0>
b'"I\xa8e\xd0\x95MK>\xe7+\x07'\xde\xe2\x13\xf6\x1e\xd2^R8\xf9.\x05z\x8b\xb5'
南来北往

(3) RSA asymmetric encryption

Extension: APP security recommendations: 1. When using RSA algorithm for digital signatures, it is recommended that the key length should not be less than 512 bits, preferably 1024 bits. 2. When using RSA encryption, if the working mode is set to ECB, it is recommended that the padding method be OAEPWithSHA256AndMGF1Padding.

import rsa 

def rsaEncrypt(str):
      # Generate public key, private key
      (pubkey,privkey)=rsa.newkeys(512)
      print("pub:",pubkey)
      print("priv:",privkey)
      content =str.encode('utf-8')

      crypto=rsa.encrypt(content,pubkey)
      return (crypto,privkey)


def rsaDecrypt(str,pk):
      content = rsa.decrypt(str,pk)
      con=content.decode('utf-8')
      return con
 (a,b)=rsaEncrypt("hello") 
print('Encrypted ciphertext:') 
print(a) 
content = rsaDecrypt(a,b) 
print(content)

Output:

pub: PublicKey(10224716067198480147617638754883355202713448141531736080412727285989130693341793946859623298056210410740038704683106707884390481307747163248998182831361163, 65537)
priv: PrivateKey(10224716067198480147617638754883355202713448141531736080412727285989130693341793946859623298056210410740038704683106707884390481307747163248998182831361163, 65537, 5400282618215789429324457144231998061960774737491485919212141878285972345666166553226592021005152635629640166074005915666141173161129536124011174050492769, 5818723586322406878415248931016889575549272227294253767355937422578481050392848819, 1757209449033268399430211948686844080896027565472554340862366664022635977)
Encrypted ciphertext:
 b'\x9e\xf1\xbd\x87S\xd2\xae\xb0]N\xec1mI\xd3mS.\xa8\xbd\x1f\xbc\xde\x96\xaf\xf0\xd7\xe3\xd0\xaf\x1b\x8c\xef\xa7\xd8\xe6\xd9\x8a\xdaL\x86Z\x13\x0e_Q\x9b\x97\xc2\xf6H\xa4=\x93\xad\x00\xfbNP\x19\xb04\xc1\xab'hello