python实现对称加密AES算法

Modes of operations allow you to encrypt more data than the block size of your symmetric block cipher. Example: CBC.

In this program, you are required to demonstrate the AES-256-CBC algorithm with a third-party crypto library, pycryptodome. Recall that you must provide a corresponding requirements.txt file if any third party libraries are involved in the code.

Your program does the following:

• Read a text string from the console input.
• Encode the text string with utf-8 encoding, as the plaintext bytes.
• Pad the plaintext bytes with pkcs7 algorithm.
• Print the padded bytes as a hex string.
• Read a Base64 string from the console input. The string represents the key bytes as a Base64 string. If the length of key bytes is not expected, abort the program with a Python code raise Exception('key length mismatch')
• Read a Base64 string from the console input. The string represents the IV bytes as a Base64 string. If the length of IV bytes is not expected, abort the program with a Python code raise Exception('IV length mismatch')
• Encrypt the padded plaintext bytes with the key and IV.
• Print the ciphertext bytes as a Base64 string.
• Decrypt the ciphertext bytes with the key and IV.
• Unpad the decrypted plaintext bytes with pkcs7 algorithm.
• Print the unpadded bytes as a hex string.
• Decode the unpadded bytes with utf-8 encoding, and print the decoded text string.

Input:

I don't like deadbeef. 你呢？ 1UO7ZnmwcT7KtScS2hAZV aZ1Gk95HPK1EqcXT6rqoU= 6GXIzJ0GD/76WkTtgmaDYQ== 

Output:

4920646f6e2774206c696b652064656164626565662e20e4bda0e591a2efbc9f10101010101010101010101010101010 c0LWy2BUg949eMO G8NgxUzKVNNFys8EzavYFhP0Tc/mZM/UVVe4E3b34cEyu1Ze not identical 4920646f6e2774206c696b652064656164626565662e20e4bda0e591a2efbc9f I don't like deadbeef. 你呢？ 

Note: the first line of the example input is consisting of the following 26 characters:

from Crypto.Cipher import AES import base64   class PrpCrypt(object):      def __init__(self, key, iv):         self.key = key         self.iv = iv         self.mode = AES.MODE_CBC      # pkcs7填充函数：     @staticmethod     def pkcs7_padding(in_bytes: str): pad_len: int = 16 - len(in_bytes) % 16 if pad_len == 0: pad_len = 16 in_str: str = str(in_bytes) + str(hex(pad_len) * pad_len).replace('0x', '') return in_str # pkcs7反填充函数： @staticmethod def pkcs7_unpadding(in_hex_str: str) -> str: end_str: str = in_hex_str[-2:] if end_str == '01': end_str: str = in_hex_str[0:-2] else: num: int = int(end_str[-2:], 16) end_str: str = in_hex_str[0:-(2 * num)] return end_str # AES加密函数： def encrypt(self, text: bytes): # Encrypt the padded plaintext bytes with the key and IV. ciphertext = AES.new(self.key, self.mode, self.iv) output_bytes: bytes = ciphertext.encrypt(bytes(text)) return output_bytes # AES解密函数： def decrypt(self, text: bytes): plaintext = AES.new(self.key, self.mode, self.iv) output_bytes = plaintext.decrypt(bytes(text)) return output_bytes if __name__ == '__main__': # Read a text string from the console input. p_str: str = input('plaintext input:') # Read a Base64 string from the console input. key_b64: str = input('key input:') key: bytes = base64.b64decode(key_b64) IV_b64: str = input('IV input:') IV: bytes = base64.b64decode(IV_b64) # 异常处理函数： def judge(bytes_1: bytes, bytes_2: bytes): if len(bytes_1) % 24 != 0: if len(bytes_1) % 16 != 0: raise Exception('key length mismatch') if len(bytes_2) % 16 != 0: raise Exception('IV length mismatch ') judge(key, IV) pc = PrpCrypt(key, IV) # 初始化密钥 # Encode the text string with utf-8 encoding, as the plaintext bytes. plaintext_str: str = p_str.encode('utf-8').hex() # Print the padded bytes as a hex string. print(pc.pkcs7_padding(plaintext_str)) padded_plaintext: bytes = bytes.fromhex(pc.pkcs7_padding(plaintext_str)) # Encrypt the padded plaintext bytes with the key and IV. ciphertext: str = base64.b64encode(pc.encrypt(padded_plaintext)).decode('utf-8') # Print the ciphertext bytes as a Base64 string. print(ciphertext) # Decrypt the ciphertext bytes with the key and IV. ciphertext_bytes: bytes = bytes.fromhex(base64.b64decode(ciphertext).hex()) plaintext: str = base64.b64encode(pc.decrypt(ciphertext_bytes)).decode('utf-8') if base64.b64decode(plaintext).hex() == ciphertext: print('identical') else: print('not identical') # Print the unpadded bytes as a hex string. print(pc.pkcs7_unpadding(base64.b64decode(plaintext).hex())) # Decode the unpadded bytes with utf-8 encoding, and print the decoded text string. text_str: str = pc.pkcs7_unpadding(base64.b64decode(plaintext).hex()) text_string: str = bytes.fromhex(text_str).decode('utf-8') print(text_string) 

plaintext input:I don't like deadbeef. 你呢？
key input:1UO7ZnmwcT7KtScS2hAZV+aZ1Gk95HPK1EqcXT6rqoU=
IV input:6GXIzJ0GD/76WkTtgmaDYQ==
4920646f6e2774206c696b652064656164626565662e20e4bda0e591a2efbc9f10101010101010101010101010101010
c0LWy2BUg949eMO+G8NgxUzKVNNFys8EzavYFhP0Tc/mZM/UVVe4E3b34cEyu1Ze
not identical
4920646f6e2774206c696b652064656164626565662e20e4bda0e591a2efbc9f
I don't like deadbeef. 你呢？

进程已结束，退出代码为 0

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python实现对称加密AES算法工程文件