python有证书的加密解密实现方法(2)

import time
from M2Crypto import X509, EVP, RSA, ASN1
def issuer_name():
    """
    证书发行人名称(专有名称)。
    Parameters:
        none
    Return:
        X509标准的发行人obj.
    """
    issuer = X509.X509_Name()
    issuer.C = "CN"                # 国家名称
    issuer.CN = "*.jb51.net"       # 普通名字
    issuer.ST = "Hunan Changsha"
    issuer.L = "Hunan Changsha"
    issuer.O = "Geekso Company Ltd"
    issuer.OU = "Geekso Company Ltd"
    issuer.Email = "123456@qq.com"
    return issuer
def make_request(bits, cn):
    """
    创建一个X509标准的请求。
    Parameters:
        bits = 证书位数
        cn = 证书名称
    Return:
        返回 X509 request 与 private key (EVP).
    """
    rsa = RSA.gen_key(bits, 65537, None)
    pk = EVP.PKey()
    pk.assign_rsa(rsa)
    req = X509.Request()
    req.set_pubkey(pk)
    name = req.get_subject()
    name.C = "US"
    name.CN = cn
    req.sign(pk,'sha256')
    return req, pk
def make_certificate_valid_time(cert, days):
    """
    从当前时间算起证书有效期几天。
    Parameters:
        cert = 证书obj
        days = 证书过期的天数
    Return:
        none
    """
    t = long(time.time()) # 获取当前时间
    time_now = ASN1.ASN1_UTCTIME()
    time_now.set_time(t)
    time_exp = ASN1.ASN1_UTCTIME()
    time_exp.set_time(t + days * 24 * 60 * 60)
    cert.set_not_before(time_now)
    cert.set_not_after(time_exp)
def make_certificate(bits):
    """
    创建证书
    Parameters:
        bits = 证快的位数
    Return:
        证书, 私钥 key (EVP) 与 公钥 key (EVP).
    """
    req, pk = make_request(bits, "localhost")
    puk = req.get_pubkey()
    cert = X509.X509()
    cert.set_serial_number(1) # 证书的序例号
    cert.set_version(1) # 证书的版本
    cert.set_issuer(issuer_name()) # 发行人信息
    cert.set_subject(issuer_name()) # 主题信息
    cert.set_pubkey(puk)
    make_certificate_valid_time(cert, 365) # 证书的过期时间
    cert.sign(pk, 'sha256')
    return cert, pk, puk
# 开始创建
cert, pk, puk= make_certificate(1024)
cert.save_pem('jb51.net-cret.pem')
pk.save_key('jb51.net-private.pem',cipher = None, callback = lambda: None)
puk.get_rsa().save_pub_key('jb51.net-public.pem')