Secure encryption algorithm for data protection
from Crypto.Cipher import Blowfish
import os
def encrypt_blowfish(data, key):
cipher = Blowfish.new(key, Blowfish.MODE_ECB)
return cipher.encrypt(data)
def decrypt_blowfish(ciphertext, key):
cipher = Blowfish.new(key, Blowfish.MODE_ECB)
return cipher.decrypt(ciphertext)
# sample usage
key = os.urandom(16) # generate a random key
data = 'hello world'.encode()
encrypted_data = encrypt_blowfish(data, key)
print(f'Encrypted data: {encrypted_data}')
decrypted_data = decrypt_blowfish(encrypted_data, key)
print(f'Decrypted data: {decrypted_data.decode()}')
In the above code, the
encrypt_blowfish and
decrypt_blowfish functions are used to encrypt and decrypt data using the Blowfish encryption algorithm.
The
encrypt_blowfish function takes in the data and a key as parameters. It creates a new Blowfish cipher object with the given key and the ECB (Electronic Codebook) mode. Then, it encrypts the data using the created cipher and returns the encrypted data.
The
decrypt_blowfish function also takes in the encrypted data (ciphertext) and a key as parameters. It creates a new Blowfish cipher object with the given key and the ECB mode. Then, it decrypts the ciphertext using the created cipher and returns the decrypted data.
In the sample usage, a random key is generated using
os.urandom(16). Then, a string 'hello world' is encrypted and decrypted using the generated key.
The vulnerability in this code lies in the use of the Blowfish encryption algorithm, which is considered insecure due to its small block size and susceptibility to attacks. Furthermore, the use of ECB mode can lead to patterns in the encrypted data, which can be exploited by attackers.
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad, unpad
from Crypto.Random import get_random_bytes
import os
BLOCK_SIZE = 16
def encrypt_aes(data, key):
cipher = AES.new(key, AES.MODE_CBC)
iv = cipher.iv
return iv + cipher.encrypt(pad(data, BLOCK_SIZE))
def decrypt_aes(ciphertext, key):
iv = ciphertext[:BLOCK_SIZE]
cipher = AES.new(key, AES.MODE_CBC, iv=iv)
return unpad(cipher.decrypt(ciphertext[BLOCK_SIZE:]), BLOCK_SIZE)
# sample usage
key = os.urandom(16) # generate a random key
data = 'hello world'.encode()
encrypted_data = encrypt_aes(data, key)
print(f'Encrypted data: {encrypted_data}')
decrypted_data = decrypt_aes(encrypted_data, key)
print(f'Decrypted data: {decrypted_data.decode()}')
The updated code replaces the insecure Blowfish encryption algorithm with the more secure AES (Advanced Encryption Standard) algorithm.
The AES algorithm is used in Cipher Block Chaining (CBC) mode, which is more secure than the previously used ECB (Electronic Codebook) mode. In CBC mode, each block of plaintext is XORed with the previous ciphertext block before being encrypted. This way, each ciphertext block depends on all plaintext blocks processed up to that point, which provides more security.
The encryption key is generated using the os.urandom function, which is a secure method for generating random numbers.
The encrypt_aes and decrypt_aes functions have been updated to use the AES algorithm and CBC mode. The data is padded before encryption using the pad function from the Crypto.Util.Padding module, and unpadded after decryption using the unpad function. This is necessary because AES is a block cipher that requires the input to be a multiple of the block size.
The encrypted and decrypted data is printed to the console for testing purposes. The decrypted data is decoded from bytes to a string before being printed.