如何使用 python 中的 RSA 私鑰進行加密？

Question

是否可以使用 pycryptodome 或任何其他庫在 python 中使用私鑰加密消息？ 我知道你不應該用私鑰加密並用公鑰解密，但我的目的是用私鑰加密，以便接收者可以確定消息是由真正的作者發送的。 不僅僅是安全加密，我正在尋找某種混淆。 我想做一個消息是公開的應用程序，但只有在您擁有公鑰時才能看到它。 我試過這樣做：

from Crypto import Random
from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
import base64


def generate_keys():
    modulus_lenght = 256 * 4
    private_key = RSA.generate(modulus_lenght, Random.new().read)
    public_key = private_key.publickey()
    return private_key, public_key

def encrypt_private_key(a_message, private_key):
    encryptor = PKCS1_OAEP.new(private_key)
    encrypted_msg = encryptor.encrypt(a_message)
    encoded_encrypted_msg = base64.b64encode(encrypted_msg)
   return encoded_encrypted_msg

def decrypt_public_key(encoded_encrypted_msg, public_key):
    encryptor = PKCS1_OAEP.new(public_key)
    decoded_encrypted_msg = base64.b64decode(encoded_encrypted_msg)
    decoded_decrypted_msg = encryptor.decrypt(decoded_encrypted_msg)
    return decoded_decrypted_msg

private_key, public_key = generate_keys()

message = "Hello world"

encoded = encrypt_private_key(message, private_key)
decoded = decrypt_public_key(encoded, public_key)

print decoded

但它引發了下一個錯誤：TypeError：這不是私鑰。

Answer 1

簡答

• 出於安全原因，您使用的代碼不允許您這樣做
• 下面的替代代碼

長答案

我對你的問題很好奇，然后我開始嘗試編碼

過了一會兒，我意識到如果你運行這個代碼段，你會看到它正常工作：

#!/usr/bin/env python

from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
import base64

def generate_keys():
    modulus_length = 1024

    key = RSA.generate(modulus_length)
    #print (key.exportKey())

    pub_key = key.publickey()
    #print (pub_key.exportKey())

    return key, pub_key

def encrypt_private_key(a_message, private_key):
    encryptor = PKCS1_OAEP.new(private_key)
    encrypted_msg = encryptor.encrypt(a_message)
    print(encrypted_msg)
    encoded_encrypted_msg = base64.b64encode(encrypted_msg)
    print(encoded_encrypted_msg)
    return encoded_encrypted_msg

def decrypt_public_key(encoded_encrypted_msg, public_key):
    encryptor = PKCS1_OAEP.new(public_key)
    decoded_encrypted_msg = base64.b64decode(encoded_encrypted_msg)
    print(decoded_encrypted_msg)
    decoded_decrypted_msg = encryptor.decrypt(decoded_encrypted_msg)
    print(decoded_decrypted_msg)
    #return decoded_decrypted_msg

def main():
  private, public = generate_keys()
  print (private)
  message = b'Hello world'
  encoded = encrypt_private_key(message, public)
  decrypt_public_key(encoded, private)

if __name__== "__main__":
  main()

但是，如果您現在將最后兩行 [即鍵的作用] 更改為：

    encoded = encrypt_private_key(message, private)
    decrypt_public_key(encoded, public)

並重新運行程序，你會得到TypeError: No private key

讓我引用這個偉大的答案：

“事實證明，PyCrypto 只是試圖防止您在這里將一個誤認為另一個，例如 OpenSSL 或 Ruby OpenSSL 允許您同時執行以下操作：public_encrypt/public_decrypt 和 private_encrypt/private_decrypt

[...]

需要注意其他事情才能使結果在實踐中可用。 這就是為什么 PyCrypto 中有一個專用的簽名包- 這有效地完成了你所描述的，而且還處理了我提到的事情”

改編此鏈接，我來到了以下應該解決您問題的代碼：

# RSA helper class for pycrypto
# Copyright (c) Dennis Lee
# Date 21 Mar 2017

# Description:
# Python helper class to perform RSA encryption, decryption, 
# signing, verifying signatures & keys generation

# Dependencies Packages:
# pycrypto 

# Documentation:
# https://www.dlitz.net/software/pycrypto/api/2.6/

from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
from Crypto.Signature import PKCS1_v1_5
from Crypto.Hash import SHA512, SHA384, SHA256, SHA, MD5
from Crypto import Random
from base64 import b64encode, b64decode
import rsa

hash = "SHA-256"

def newkeys(keysize):
    random_generator = Random.new().read
    key = RSA.generate(keysize, random_generator)
    private, public = key, key.publickey()
    return public, private

def importKey(externKey):
    return RSA.importKey(externKey)

def getpublickey(priv_key):
    return priv_key.publickey()

def encrypt(message, pub_key):
    #RSA encryption protocol according to PKCS#1 OAEP
    cipher = PKCS1_OAEP.new(pub_key)
    return cipher.encrypt(message)

def decrypt(ciphertext, priv_key):
    #RSA encryption protocol according to PKCS#1 OAEP
    cipher = PKCS1_OAEP.new(priv_key)
    return cipher.decrypt(ciphertext)

def sign(message, priv_key, hashAlg="SHA-256"):
    global hash
    hash = hashAlg
    signer = PKCS1_v1_5.new(priv_key)
    if (hash == "SHA-512"):
        digest = SHA512.new()
    elif (hash == "SHA-384"):
        digest = SHA384.new()
    elif (hash == "SHA-256"):
        digest = SHA256.new()
    elif (hash == "SHA-1"):
        digest = SHA.new()
    else:
        digest = MD5.new()
    digest.update(message)
    return signer.sign(digest)

def verify(message, signature, pub_key):
    signer = PKCS1_v1_5.new(pub_key)
    if (hash == "SHA-512"):
        digest = SHA512.new()
    elif (hash == "SHA-384"):
        digest = SHA384.new()
    elif (hash == "SHA-256"):
        digest = SHA256.new()
    elif (hash == "SHA-1"):
        digest = SHA.new()
    else:
        digest = MD5.new()
    digest.update(message)
    return signer.verify(digest, signature)

def main():
    msg1 = b"Hello Tony, I am Jarvis!"
    msg2 = b"Hello Toni, I am Jarvis!"

    keysize = 2048

    (public, private) = rsa.newkeys(keysize)

    # https://docs.python.org/3/library/base64.html
    # encodes the bytes-like object s
    # returns bytes
    encrypted = b64encode(rsa.encrypt(msg1, private))
    # decodes the Base64 encoded bytes-like object or ASCII string s
    # returns the decoded bytes
    decrypted = rsa.decrypt(b64decode(encrypted), private)
    signature = b64encode(rsa.sign(msg1, private, "SHA-512"))

    verify = rsa.verify(msg1, b64decode(signature), public)

    #print(private.exportKey('PEM'))
    #print(public.exportKey('PEM'))
    print("Encrypted: " + encrypted.decode('ascii'))
    print("Decrypted: '%s'" % (decrypted))
    print("Signature: " + signature.decode('ascii'))
    print("Verify: %s" % verify)
    rsa.verify(msg2, b64decode(signature), public)

if __name__== "__main__":
    main()

最后說明：

• 最后print ■找ascii因為說這里“為Base64的情況下，但是，所有的字符都是有效的ASCII字符”
• 在這種情況下，我們使用相同的密鑰 - 私有密鑰 - 用於加密和解密，所以是的：我們最終會是對稱的，但是......
• 但是 - 正如這里所說 - “公鑰是公開的 - 它是你很容易共享的東西，因此很容易傳播。與使用對稱密碼和共享密鑰相比，在這種情況下沒有附加價值”加上“概念上，”加密“使用私鑰對消息簽名更有用，而使用公鑰的“解密”用於驗證消息”
• 在這個答案中表達了相同的最后一個原則 - “通常[...]我們說用私鑰簽名並用公鑰驗證”

Answer 2

看起來pycrypto自 2014 年以來一直沒有積極開發，支持在 python 3.3 結束。 cryptography現在似乎是標准。

使用cryptography ：

from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.backends import default_backend

password = b'thepassword'

key = rsa.generate_private_key(
    backend=default_backend(),
    public_exponent=65537,
    key_size=2048
)

private_key = key.private_bytes(
    serialization.Encoding.PEM,
    serialization.PrivateFormat.PKCS8,
    serialization.BestAvailableEncryption(password)
)

public_key = key.public_key().public_bytes(
    serialization.Encoding.OpenSSH,
    serialization.PublicFormat.OpenSSH
)

Answer 3

您所描述的稱為消息簽名，它使用私鑰/公鑰來驗證消息確實來自聲稱的發件人，並且在途中沒有被篡改。 你不必“發明”這些方法......

https://medium.com/@securegns/implementing-asymmetric-encryption-to-secure-your-project-35368049cb5f