如何检查ssl证书（X509 V1）是否是没有证书扩展字段的CA证书？

Question

我在Java中有一个X509Certificate（版本1）实例，我需要确定它是CA证书还是用户证书。

我尝试了这个How to check if X509Certificate is CA certificate?，但是根据那里提供的解决方案，我可以区分具有certificateExtension的证书（通过利用getBasicConstraints（）方法并检查keyUsage中的keyCertSign标志，即V3证书将具有扩展字段v1或v2不会有）

if (x509Cert != null) {
    isCA = x509Cert.getBasicConstraints() != -1 ? true : false;
}

但是我在X509Certificate实例中没有几个没有certificateExtension字段的证书（因为它们是V1版本证书），因此我将isCA标记为false。我也尝试在https://certlogik.com/decoder/这样的在线ssl解码器中解码证书，我可以区分证书类型！

以编程方式查找没有certificateExtension的证书类型的任何其他方法？

样本CA证书：

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

It's X509
[
[
  Version: V1
  Subject: CN=GTE CyberTrust Global Root, OU="GTE CyberTrust Solutions, Inc.", O=GTE Corporation, C=US
  Signature Algorithm: MD5withRSA, OID = 1.2.840.113549.1.1.4

  Key:  Sun RSA public key, 1024 bits
  modulus: 104674226241368487598835828377585222181792546532354327780214427055917513664449991602803276678454577364904540367827644455215731003386468752240014232146814457308076052176227490263634768927290191763858631579785604655038492469791381988347440106477066514204303723029602991655085187937840556671697442212352844587673
  public exponent: 65537
  Validity: [From: Thu Aug 13 05:59:00 IST 1998,
           To: Tue Aug 14 05:29:00 IST 2018]
  Issuer: CN=GTE CyberTrust Global Root, OU="GTE CyberTrust Solutions, Inc.", O=GTE Corporation, C=US
  SerialNumber: [    01a5]

]
  Algorithm: [MD5withRSA]
  Signature:
0000: 6D EB 1B 09 E9 5E D9 51   DB 67 22 61 A4 2A 3C 48  m....^.Q.g"a.*<H
0010: 77 E3 A0 7C A6 DE 73 A2   14 03 85 3D FB AB 0E 30  w.....s....=...0
0020: C5 83 16 33 81 13 08 9E   7B 34 4E DF 40 C8 74 D7  ...3.....4N.@.t.
0030: B9 7D DC F4 76 55 7D 9B   63 54 18 E9 F0 EA F3 5C  ....vU..cT.....\
0040: B1 D9 8B 42 1E B9 C0 95   4E BA FA D5 E2 7C F5 68  ...B....N......h
0050: 61 BF 8E EC 05 97 5F 5B   B0 D7 A3 85 34 C4 24 A7  a....._[....4.$.
0060: 0D 0F 95 93 EF CB 94 D8   9E 1F 9D 5C 85 6D C7 AA  ...........\.m..
0070: AE 4F 1F 22 B5 CD 95 AD   BA A7 CC F9 AB 0B 7A 7F  .O."..........z.

]

解码证书文件内容时，它显示为CA证书

提前谢谢！