我目前正在开发一个使用 Crypto 库进行 AES 加密和解密的 Python 脚本。加密部分似乎工作正常,但当我尝试解密文本时,结果是一个空字符串。我已经检查了我的代码,但无法确定问题所在。如果有任何见解或建议可以帮助我调试和解决此问题,我将不胜感激。
import hashlib
from Crypto.Cipher import AES
from Crypto import Random
from base64 import b64encode, b64decode
class AESCipher(object):
def __init__(self, key=None):
# Initialize the AESCipher object with a key, defaulting to a randomly generated key
self.block_size = AES.block_size
if key:
self.key = hashlib.sha256(key.encode()).digest()
else:
self.key = Random.new().read(self.block_size)
def encrypt(self, plain_text):
# Encrypt the provided plaintext using AES in CBC mode
plain_text = self.__pad(plain_text)
iv = Random.new().read(self.block_size)
cipher = AES.new(self.key, AES.MODE_CBC, iv)
encrypted_text = cipher.encrypt(plain_text)
# Combine IV and encrypted text, then base64 encode for safe representation
return b64encode(iv + encrypted_text).decode("utf-8")
def decrypt(self, encrypted_text):
# Decrypt the provided ciphertext using AES in CBC mode
encrypted_text = b64decode(encrypted_text)
iv = encrypted_text[:self.block_size]
cipher = AES.new(self.key, AES.MODE_CBC, iv)
plain_text = cipher.decrypt(encrypted_text[self.block_size:])
return self.__unpad(plain_text)
def get_key(self):
# Get the base64 encoded representation of the key
return b64encode(self.key).decode("utf-8")
def __pad(self, plain_text):
# Add PKCS7 padding to the plaintext
number_of_bytes_to_pad = self.block_size - len(plain_text) % self.block_size
padding_bytes = bytes([number_of_bytes_to_pad] * number_of_bytes_to_pad)
padded_plain_text = plain_text.encode() + padding_bytes
return padded_plain_text
@staticmethod
def __unpad(plain_text):
# Remove PKCS7 padding from the plaintext
last_byte = plain_text[-1]
return plain_text[:-last_byte] if isinstance(last_byte, int) else plain_text
def save_to_notepad(text, key, filename):
# Save encrypted text and key to a file
with open(filename, 'w') as file:
file.write(f"Key: {key}\nEncrypted text: {text}")
print(f"Text and key saved to {filename}")
def encrypt_and_save():
# Take user input, encrypt, and save to a file
user_input = ""
while not user_input:
user_input = input("Enter the plaintext: ")
aes_cipher = AESCipher() # Randomly generated key
encrypted_text = aes_cipher.encrypt(user_input)
key = aes_cipher.get_key()
filename = input("Enter the filename (including .txt extension): ")
save_to_notepad(encrypted_text, key, filename)
def decrypt_from_file():
# Decrypt encrypted text from a file using a key
filename = input("Enter the filename to decrypt (including .txt extension): ")
with open(filename, 'r') as file:
lines = file.readlines()
key = lines[0].split(":")[1].strip()
encrypted_text = lines[1].split(":")[1].strip()
aes_cipher = AESCipher(key)
decrypted_bytes = aes_cipher.decrypt(encrypted_text)
# Decoding only if the decrypted bytes are not empty
decrypted_text = decrypted_bytes.decode("utf-8") if decrypted_bytes else ""
print("Decrypted Text:", decrypted_text)
def encrypt_and_decrypt_in_command_line():
# Encrypt and then decrypt user input in the command line
user_input = ""
while not user_input:
user_input = input("Enter the plaintext: ")
aes_cipher = AESCipher()
encrypted_text = aes_cipher.encrypt(user_input)
key = aes_cipher.get_key()
print("Key:", key)
print("Encrypted Text:", encrypted_text)
decrypted_bytes = aes_cipher.decrypt(encrypted_text)
decrypted_text = decrypted_bytes.decode("utf-8") if decrypted_bytes else ""
print("Decrypted Text:", decrypted_text)
# Menu Interface
while True:
print("\nMenu:")
print("1. Encrypt and save to file")
print("2. Decrypt from file")
print("3. Encrypt and decrypt in command line")
print("4. Exit")
choice = input("Enter your choice (1, 2, 3, or 4): ")
if choice == '1':
encrypt_and_save()
elif choice == '2':
decrypt_from_file()
elif choice == '3':
encrypt_and_decrypt_in_command_line()
elif choice == '4':
print("Exiting the program. Goodbye!")
break
else:
print("Invalid choice. Please enter 1, 2, 3, or 4.")
AESCipher.get_key
方法将密钥编码为 Base64 字符串。
当您在
AESCipher
构造函数中提供密钥时,您需要解码密钥而不是计算摘要。
您的构造函数应如下所示:
class AESCipher(object):
def __init__(self, key=None):
# Initialize the AESCipher object with a key,
# defaulting to a randomly generated key
self.block_size = AES.block_size
if key:
self.key = b64decode(key.encode())
else:
self.key = Random.new().read(self.block_size)