python 支付宝证书 计算SN 序列号

网上没看到有python写的算支付宝公钥证书与根证书序列号得，只有java与php，我python怎么能没有呢 整上！

 

安装pyOpenSSL

pip install pyOpenSSL

# coding=utf-8
# author wangdada
import OpenSSL
import hashlib
import re


def md5(string):
    return hashlib.md5(string.encode('utf-8')).hexdigest()


# 应用公钥证书序列号
def get_app_cert_cn(cert_str=None):
    cert_str = cert_str or open("appCertPublicKey_2021001117612947.crt").read()
    cert = OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM, cert_str)
    try:
        res = cert.get_signature_algorithm()
        # 根据其他语言算法　应该剔除不是sha加密的部分python2 可以用r'sha.+WithRSAEncryption'　但是python３必须是b'sha.+WithRSAEncryption'
        if not re.match(b'sha.+WithRSAEncryption', res):
            return None
    except:
        return None
    cert_issue = cert.get_issuer()
    op = '