Python中的RSA加密和解密

Posted 2023-03-29

【中文标题】Python中的RSA加密和解密

【英文标题】：RSA encryption and decryption in Python

【发布时间】：2015-07-15 09:51:34

【问题描述】：

我需要在 Python 中使用 RSA 加密和解密的帮助。

我正在创建一个私钥/公钥对，使用密钥加密消息并将消息写入文件。然后我从文件中读取密文并使用密钥解密文本。

我在解密部分遇到问题。正如您在下面的代码中看到的那样，当我输入decrypted = key.decrypt(message) 时，程序可以工作，但解密的消息再次被加密。似乎它没有从文件中读取密文。

谁能帮我写这段代码，以便解密从文件中读取密文，然后使用密钥解密密文？

import Crypto
from Crypto.PublicKey import RSA
from Crypto import Random

random_generator = Random.new().read
key = RSA.generate(1024, random_generator) #generate public and private keys

publickey = key.publickey # pub key export for exchange

encrypted = publickey.encrypt('encrypt this message', 32)
#message to encrypt is in the above line 'encrypt this message'

print 'encrypted message:', encrypted #ciphertext

f = open ('encryption.txt', 'w'w)
f.write(str(encrypted)) #write ciphertext to file
f.close()

#decrypted code below

f = open ('encryption.txt', 'r')
message = f.read()

decrypted = key.decrypt(message)

print 'decrypted', decrypted

f = open ('encryption.txt', 'w')
f.write(str(message))
f.write(str(decrypted))
f.close()

【问题讨论】：

我在解密部分遇到问题 不能很好地描述您的问题。请阅读How to ask。你应该edit你的问题包括你的输入、输出和你的预期输出。

编辑有所帮助，但如果您包含程序的输出以及您期望的输出，它仍然会有所帮助

您的代码中有多个拼写错误。那么你实际尝试了什么？

请记住，这是"Textbook RSA"，这是弱，尤其是对于短消息。填充（通过 PKCS#1）解决了 PyCrypto（和 PyCryptodome，维护的分支）可以解决的这些问题。

相关：How to encrypt a string using the key

【参考方案1】：

为了使其工作，您需要在解密之前将密钥从 str 转换为元组（ast.literal_eval 函数）。这是固定代码：

import Crypto
from Crypto.PublicKey import RSA
from Crypto import Random
import ast

random_generator = Random.new().read
key = RSA.generate(1024, random_generator) #generate pub and priv key

publickey = key.publickey() # pub key export for exchange

encrypted = publickey.encrypt('encrypt this message', 32)
#message to encrypt is in the above line 'encrypt this message'

print('encrypted message:', encrypted) #ciphertext
f = open ('encryption.txt', 'w')
f.write(str(encrypted)) #write ciphertext to file
f.close()

#decrypted code below

f = open('encryption.txt', 'r')
message = f.read()


decrypted = key.decrypt(ast.literal_eval(str(encrypted)))

print('decrypted', decrypted)

f = open ('encryption.txt', 'w')
f.write(str(message))
f.write(str(decrypted))
f.close()

【讨论】：

成功了！太感谢了！我从来没有想过要添加它。感谢您的帮助！

@Alysson PyCrypto 文档中提到了 publickey.encrypt(): "you should not directly encrypt data with this method"，它建议使用 PKCS#1 OAEP 代替（对于代码示例，请点击链接）

能否请您为 Python 3.3+ 制作一个版本？

encrypted = publickey.encrypt('encrypt this message', 32) - pow() 不支持的操作数类型：'str', 'int', 'int'

【参考方案2】：

PKCS#1 OAEP 是一种基于 RSA 和 OAEP 填充的非对称密码

from Crypto.PublicKey import RSA
from Crypto import Random
from Crypto.Cipher import PKCS1_OAEP


def rsa_encrypt_decrypt():
    key = RSA.generate(2048)
    private_key = key.export_key('PEM')
    public_key = key.publickey().exportKey('PEM')
    message = input('plain text for RSA encryption and decryption:')
    message = str.encode(message)

    rsa_public_key = RSA.importKey(public_key)
    rsa_public_key = PKCS1_OAEP.new(rsa_public_key)
    encrypted_text = rsa_public_key.encrypt(message)
    #encrypted_text = b64encode(encrypted_text)

    print('your encrypted_text is : '.format(encrypted_text))


    rsa_private_key = RSA.importKey(private_key)
    rsa_private_key = PKCS1_OAEP.new(rsa_private_key)
    decrypted_text = rsa_private_key.decrypt(encrypted_text)

    print('your decrypted_text is : '.format(decrypted_text))

【讨论】：

你不可能用这种方法来加密整个文件

_RSAobj 对象没有“export_key”属性

【参考方案3】：

# coding: utf-8
from __future__ import unicode_literals
import base64
import os

import six
from Crypto import Random
from Crypto.PublicKey import RSA


class PublicKeyFileExists(Exception): pass


class RSAEncryption(object):
    PRIVATE_KEY_FILE_PATH = None
    PUBLIC_KEY_FILE_PATH = None

    def encrypt(self, message):
        public_key = self._get_public_key()
        public_key_object = RSA.importKey(public_key)
        random_phrase = 'M'
        encrypted_message = public_key_object.encrypt(self._to_format_for_encrypt(message), random_phrase)[0]
        # use base64 for save encrypted_message in database without problems with encoding
        return base64.b64encode(encrypted_message)

    def decrypt(self, encoded_encrypted_message):
        encrypted_message = base64.b64decode(encoded_encrypted_message)
        private_key = self._get_private_key()
        private_key_object = RSA.importKey(private_key)
        decrypted_message = private_key_object.decrypt(encrypted_message)
        return six.text_type(decrypted_message, encoding='utf8')

    def generate_keys(self):
        """Be careful rewrite your keys"""
        random_generator = Random.new().read
        key = RSA.generate(1024, random_generator)
        private, public = key.exportKey(), key.publickey().exportKey()

        if os.path.isfile(self.PUBLIC_KEY_FILE_PATH):
            raise PublicKeyFileExists('Файл с публичным ключом существует. Удалите ключ')
        self.create_directories()

        with open(self.PRIVATE_KEY_FILE_PATH, 'w') as private_file:
            private_file.write(private)
        with open(self.PUBLIC_KEY_FILE_PATH, 'w') as public_file:
            public_file.write(public)
        return private, public

    def create_directories(self, for_private_key=True):
        public_key_path = self.PUBLIC_KEY_FILE_PATH.rsplit('/', 1)
        if not os.path.exists(public_key_path):
            os.makedirs(public_key_path)
        if for_private_key:
            private_key_path = self.PRIVATE_KEY_FILE_PATH.rsplit('/', 1)
            if not os.path.exists(private_key_path):
                os.makedirs(private_key_path)

    def _get_public_key(self):
        """run generate_keys() before get keys """
        with open(self.PUBLIC_KEY_FILE_PATH, 'r') as _file:
            return _file.read()

    def _get_private_key(self):
        """run generate_keys() before get keys """
        with open(self.PRIVATE_KEY_FILE_PATH, 'r') as _file:
            return _file.read()

    def _to_format_for_encrypt(value):
        if isinstance(value, int):
            return six.binary_type(value)
        for str_type in six.string_types:
            if isinstance(value, str_type):
                return value.encode('utf8')
        if isinstance(value, six.binary_type):
            return value

并使用

KEYS_DIRECTORY = settings.SURVEY_DIR_WITH_ENCRYPTED_KEYS

class TestingEncryption(RSAEncryption):
    PRIVATE_KEY_FILE_PATH = KEYS_DIRECTORY + 'private.key'
    PUBLIC_KEY_FILE_PATH = KEYS_DIRECTORY + 'public.key'


# django/flask
from django.core.files import File

class ProductionEncryption(RSAEncryption):
    PUBLIC_KEY_FILE_PATH = settings.SURVEY_DIR_WITH_ENCRYPTED_KEYS + 'public.key'

    def _get_private_key(self):
        """run generate_keys() before get keys """
        from corportal.utils import global_elements
        private_key = global_elements.request.FILES.get('private_key')
        if private_key:
            private_key_file = File(private_key)
            return private_key_file.read()

message = 'Hello мой friend'
encrypted_mes = ProductionEncryption().encrypt(message)
decrypted_mes = ProductionEncryption().decrypt(message)

【参考方案4】：

这是我对 python 3 和 pycrypto 的实现

from Crypto.PublicKey import RSA
key = RSA.generate(4096)
f = open('/home/john/Desktop/my_rsa_public.pem', 'wb')
f.write(key.publickey().exportKey('PEM'))
f.close()
f = open('/home/john/Desktop/my_rsa_private.pem', 'wb')
f.write(key.exportKey('PEM'))
f.close()

f = open('/home/john/Desktop/my_rsa_public.pem', 'rb')
f1 = open('/home/john/Desktop/my_rsa_private.pem', 'rb')
key = RSA.importKey(f.read())
key1 = RSA.importKey(f1.read())

x = key.encrypt(b"dddddd",32)

print(x)
z = key1.decrypt(x)
print(z)

【讨论】：

你能解释一下如何对加密结果进行Base 64编码吗？

你使用过哪个 Crypto 模块（例如 pycrypto）？

pycryptodome pycryptodome.readthedocs.io/en/latest 是完整的文档

对base64encode结果，可以import base64再base64.b64encode(encrypted)。

【参考方案5】：

您可以使用简单的方法生成 RSA 。使用 rsa 库

pip install rsa 

【参考方案6】：

from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP

secret_message = b'ATTACK AT DAWN'

### First, make a key and save it
key = RSA.generate(2048)
with open( 'mykey.pem', 'wb' ) as f:
    f.write( key.exportKey( 'PEM' ))
 
### Then use key to encrypt and save our message
public_crypter = PKCS1_OAEP.new( key )
enc_data = public_crypter.encrypt( secret_message )
with open( 'encrypted.txt', 'wb' ) as f:
    f.write( enc_data )

### And later on load and decode
with open( 'mykey.pem', 'r' ) as f:
    key = RSA.importKey( f.read() )

with open( 'encrypted.txt', 'rb' ) as f:
    encrypted_data = f.read()

public_crypter =  PKCS1_OAEP.new( key )
decrypted_data = public_crypter.decrypt( encrypted_data )

【讨论】：

只有代码的答案通常没有用。

【参考方案7】：

小心使用加密货币！！！ 这是一个很棒的库，但它在 python3.8 中有一个问题，因为从库中删除了属性时钟（）。要修复它，只需修改 /usr/lib/python3.8/site-packages/Crypto/Random/_UserFriendlyRNG.pyline 77 中的源更改 t = time.clock() int t = time.perf_counter()

【讨论】：

欢迎来到***！您的帖子描述性不足以回答 OP 的问题。见how to write good answers。