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python-3.x - 使用 Python3 OpenSSL 库解密 S/MIME

问题描述

我有以下问题。我需要创建一个 Python 程序，我可以在其中从主机下载任何邮件并使用给定的.pfx文件和密码对其进行解密。我正在尝试各种解决方案，但现在我被困在试图强制 OpenSSL.crypto 用给定的私钥和证书简单地破译任何东西。Google 上的文档和提供的解决方案也很少。有任何想法吗？

这是我的代码：

import pickle, email

file = open('cipher.pickle', 'rb')
msg_data = pickle.load(file)
file.close()

data = msg_data[0]
response = tuple(data)[1]
msg = email.message_from_bytes(response)
message = msg.get_payload()
# message = bytes(message, encoding='utf-8)

print(message) 
#gives encrypted message: 'MIAGCSqGSIb3DQEHA6CAMIACA...14g/EwQIyhd0YOdnRR0AAAAAAAAAAAAA'

from OpenSSL import crypto
ssl_pass1 = "7F63CfcUauAf"
#generated certificate from https://extrassl.actalis.it/portal/uapub/freemail?lang=en for yahoo testmail
#together with password for this certificate
with open('testmail1_yahoo.pfx', 'rb') as f:
    pfx_data = f.read() 

pfx = crypto.load_pkcs12(pfx_data, bytes(ssl_pass1, encoding='utf-8'))
pem = crypto.dump_privatekey(crypto.FILETYPE_PEM, pfx.get_privatekey())
cert = crypto.dump_certificate(crypto.FILETYPE_PEM, pfx.get_certificate())

#private key and certificate extracted from pfx so far

标签： python-3.xopensslcryptography

解决方案

找到了。

from M2Crypto import BIO, Rand, SMIME, X509, EVP
from OpenSSL import crypto

def get_pfx(fname, password):
    f = open(fname, 'rb')
    pfx_data = f.read()
    f.close()
    pfx = crypto.load_pkcs12(pfx_data, bytes(password, encoding='utf-8'))
    return pfx

def get_cert(pfx):
    cert = pfx.get_certificate()
    fx509 = crypto.dump_certificate(crypto.FILETYPE_PEM, cert)
    x509 = X509.load_cert_string(fx509)
    return x509

def get_pkey(pfx):
    pkey = pfx.get_privatekey()
    fkey = crypto.dump_privatekey(crypto.FILETYPE_PEM, pkey)
    pkey = EVP.load_key_string(fkey)
    return pkey

def encrypt(message, x509):
    data = bytes(message, encoding='utf-8')
    buf = BIO.MemoryBuffer(data)
    sk = X509.X509_Stack()
    sk.push(x509)
    s = SMIME.SMIME()
    s.set_x509_stack(sk)
    s.set_cipher(SMIME.Cipher('aes_256_cbc'))
    p7 = s.encrypt(buf)
    return p7

def decrypt(p7, pkey, x509):
    s = SMIME.SMIME()
    s.pkey = pkey
    s.x509 = x509
    out = s.decrypt(p7)
    return_message = str(out, encoding='utf-8')
    return return_message

def decrypt_str(message, pkey, x509):
    header='Content-Type: application/x-pkcs7-mime; smime-type=enveloped-data; name="smime.p7m"\n\n'
    full_message = bytes(header + message, encoding='utf-8')
    b2 = BIO.MemoryBuffer(full_message)
    p7 = SMIME.smime_load_pkcs7_bio(b2)[0]
    out_message = decrypt(p7, pkey, x509)
    return out_message

pfx = get_pfx('testmail1_yahoo.pfx', '7F63CfcUauAf')
pkey = get_pkey(pfx)
x509 = get_cert(pfx)

ciphered_message = '''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'''

deciphered_message = decrypt_str(msg, pkey, x509)
print(deciphered_message)

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