Simple XOR Cipher in Python3

xor_cipher.py

#!/usr/bin/env python3
# Simple XOR cipher
# U+0A75

def xor_cipher(data, key):

    for i in range(len(data)):      # iterate through the message bytes
        j = i % len(key)            # rotate index of key bytes (modulo)
        data[i] = data[i] ^ key[j]  # xor current data byte with key byte

    return data

# Example
encoding = "utf-8"
message = bytearray("Hallo world, such a nice day", encoding)
password = bytearray("hunter2!#+", encoding)
print(message)

encrypted = xor_cipher(data=message, key=password)
print(encrypted) # Encrypted message

decrypted = xor_cipher(data=encrypted, key=password)
print(decrypted) # Original message is restored
print(decrypted.decode(encoding))