python - xml签名验证失败

Question

我已经使用 openssl 命令生成了私钥和公共证书：

openssl req -x509 -newkey rsa:4096 -keyout private_key.pem -out public_cert.pem -nodes -days 1460 -subj "/C=YOURCOUNTRY/O=YOURCOMPANYNAME/CN=COMMONNAME

使用上面生成的私钥对xml进行签名并尝试验证相同，但验证失败，示例代码如下：

from lxml import etree
import os
from signxml import XMLSigner, XMLVerifier


current_path = os.path.dirname(os.path.abspath(__file__))
ca_cert_file = os.path.join(current_path, "public_cert.pem")
cert = open(ca_cert_file).read()
key = open(os.path.join(current_path, "private_key.pem")).read()

data_to_sign = "<Test/>"
root = etree.fromstring(data_to_sign)
signer = XMLSigner(c14n_algorithm='http://www.w3.org/TR/2001/REC-xml-c14n-20010315')
signed_root = signer.sign(root, key=key, cert=cert)
verified_data = XMLVerifier().verify(signed_root, ca_pem_file=ca_cert_file)

执行上述代码导致以下异常：

Traceback (most recent call last):
  File "C:\Users\<username>\AppData\Local\Programs\Python\Python38-32\lib\site-packages\signxml\__init__.py", line 864, in verify
    verify(signing_cert, raw_signature, signed_info_c14n, signature_digest_method)
  File "C:\Users\<username>\AppData\Local\Programs\Python\Python38-32\lib\site-packages\OpenSSL\crypto.py", line 2869, in verify
    _raise_current_error()
  File "C:\Users\<username>\AppData\Local\Programs\Python\Python38-32\lib\site-packages\OpenSSL\_util.py", line 54, in exception_from_error_queue
    raise exception_type(errors)
OpenSSL.crypto.Error: [('rsa routines', 'RSA_padding_check_PKCS1_type_1', 'invalid padding'), ('rsa routines', 'rsa_ossl_public_decrypt', 'padding check failed')]

Answer 1

invalid padding 警告通常表示按键有问题。例如：“公钥与解密的私钥不匹配。”

当我故意不匹配我的键时，我能够抛出这个错误。此错误与您在问题中提到的相同。

OpenSSL.crypto.Error: [('rsa routines', 'RSA_padding_check_PKCS1_type_1', 'invalid padding'), ('rsa routines', 'rsa_ossl_public_decrypt', 'padding check failed')]

我建议重新创建密钥，确认您在代码中使用了正确的密钥对，然后重新测试。

我以这种方式生成了我的密钥。

openssl req -x509 -newkey rsa:4096 -keyout private_key.pem -out public_cert.pem -nodes -days 1460 -subj "/C=US/O=mycompanyname/CN=domainname.com"

下面的代码没有产生错误。

import os
from lxml import etree
from signxml import XMLSigner, XMLVerifier, InvalidCertificate

current_path = os.path.dirname(os.path.abspath(__file__))
ca_cert_file = os.path.join(current_path, "public_cert.pem")
cert = open(ca_cert_file).read()
key = open(os.path.join(current_path, "private_key.pem")).read()

data_to_sign = "<Test/>"
root = etree.fromstring(data_to_sign)
signer = XMLSigner(c14n_algorithm='http://www.w3.org/TR/2001/REC-xml-c14n-20010315')
signed_root = signer.sign(root, key=key, cert=cert)
try:
    verified_data = XMLVerifier().verify(signed_root, ca_pem_file=ca_cert_file)
except InvalidCertificate as e:
    print(e)
else:
    print('verified signature')

----------------------------------------
 System information
----------------------------------------
Platform:    macOS
Python:      3.8.0
lxml:        4.6.2
signxml:     2.8.1
LibreSSL:    2.8.3 (openssl)
----------------------------------------