python-2.7 – 使用pyopenssl创建自签名证书

我正在尝试使用pyopenssl生成ac自签名X509v3 CA证书.
我想要添加扩展权限密钥标识符(AKID)与包含主题密钥标识符(SKID)的keyid.
但我的以下代码块不会将SKID复制到AKID而是抛出异常.
请帮我解决这个问题:)
代码如下

import OpenSSL

key = OpenSSL.crypto.PKey()
key.generate_key(OpenSSL.crypto.TYPE_RSA,2048)

ca = OpenSSL.crypto.X509()
ca.set_version(2)
ca.set_serial_number(1)
ca.get_subject().CN = "ca.example.com"
ca.gmtime_adj_notBefore(0)
ca.gmtime_adj_notAfter(24 * 60 * 60)
ca.set_issuer(ca.get_subject())
ca.set_pubkey(key)
ca.add_extensions([
  OpenSSL.crypto.X509Extension("basicConstraints",True,"CA:TRUE,pathlen:0"),OpenSSL.crypto.X509Extension("keyUsage","keyCertSign,cRLSign"),OpenSSL.crypto.X509Extension("subjectKeyIdentifier",False,"hash",subject=ca),OpenSSL.crypto.X509Extension("authorityKeyIdentifier","keyid:always",issuer=ca)
  ])
ca.sign(key,"sha1")
open("MyCertificate.crt.bin","wb").write(
            OpenSSL.crypto.dump_certificate(OpenSSL.crypto.FILETYPE_ASN1,ca))

抛出的异常如下

Traceback (most recent call last):
  File "C:\Documents and Settings\Administrator\Desktop\Certificate\certi.py",line 21,in <module>
    OpenSSL.crypto.X509Extension("authorityKeyIdentifier",issuer=ca)
Error: [('X509 V3 routines','V2I_AUTHORITY_KEYID','unable to get issuer keyid'),('X509 V3 routines','X509V3_EXT_nconf','error in extension')]

现在,如果我从代码的下面一行中的行keyid参数中删除“always”

OpenSSL.crypto.X509Extension(“authorityKeyIdentifier”,
“keyid”,issuer=ca)

我得到AKID keyid字段为空,它不包含SKID,如下所示

00:84:13:70:73:fe:29:61:5f:33:7d:b3:74:97:3b:
            3a:f3:11:01:7c:b8:37:a8:8c:72:81:ee:92:fd:91:
            8a:11:b3:b3:02:b4:97:d5:f8:1b:91:54:7e:15:49:
            26:6d
        Exponent: 65537 (0x10001)
X509v3 extensions:
    X509v3 Basic Constraints: critical
        CA:TRUE,pathlen:0
    X509v3 Key Usage: critical
        Certificate Sign,CRL Sign
    X509v3 Subject Key Identifier: 
        CE:D1:31:DE:CF:E3:E2:BC:6C:73:3D:55:F0:88:53:0A:F1:DC:31:14
    X509v3 Authority Key Identifier: 
        0.
Signature Algorithm: sha1WithRSAEncryption
     0b:7b:28:f6:b9:1e:6e:ec:53:6a:c5:77:db:c5:3f:5e:1d:ab:
     e5:43:73:eb:52:24:af:39:2b:aa:a3:f6:34:e1:92:4b:3b:5e:
     b6:1

提前谢谢你.

ca.add_extensions([
  OpenSSL.crypto.X509Extension("basicConstraints",])
ca.add_extensions([
  OpenSSL.crypto.X509Extension("authorityKeyIdentifier",issuer=ca)
  ])