在没有 BouncyCastle 的情况下用 Java 创建 X509 证书？

Question

是否可以在不使用 Bouncy Castle X509V*CertificateGenerator 类的情况下用 Java 代码创建 X509 证书？

Answer 1

是的，但不是公开记录的课程。我已经记录了这个过程in this article。

import sun.security.x509.*;
import java.security.cert.*;
import java.security.*;
import java.math.BigInteger;
import java.util.Date;
import java.io.IOException

/** 
 * Create a self-signed X.509 Certificate
 * @param dn the X.509 Distinguished Name, eg "CN=Test, L=London, C=GB"
 * @param pair the KeyPair
 * @param days how many days from now the Certificate is valid for
 * @param algorithm the signing algorithm, eg "SHA1withRSA"
 */ 
X509Certificate generateCertificate(String dn, KeyPair pair, int days, String algorithm)
  throws GeneralSecurityException, IOException
{
  PrivateKey privkey = pair.getPrivate();
  X509CertInfo info = new X509CertInfo();
  Date from = new Date();
  Date to = new Date(from.getTime() + days * 86400000l);
  CertificateValidity interval = new CertificateValidity(from, to);
  BigInteger sn = new BigInteger(64, new SecureRandom());
  X500Name owner = new X500Name(dn);
 
  info.set(X509CertInfo.VALIDITY, interval);
  info.set(X509CertInfo.SERIAL_NUMBER, new CertificateSerialNumber(sn));
  info.set(X509CertInfo.SUBJECT, new CertificateSubjectName(owner));
  info.set(X509CertInfo.ISSUER, new CertificateIssuerName(owner));
  info.set(X509CertInfo.KEY, new CertificateX509Key(pair.getPublic()));
  info.set(X509CertInfo.VERSION, new CertificateVersion(CertificateVersion.V3));
  AlgorithmId algo = new AlgorithmId(AlgorithmId.md5WithRSAEncryption_oid);
  info.set(X509CertInfo.ALGORITHM_ID, new CertificateAlgorithmId(algo));
 
  // Sign the cert to identify the algorithm that's used.
  X509CertImpl cert = new X509CertImpl(info);
  cert.sign(privkey, algorithm);
 
  // Update the algorith, and resign.
  algo = (AlgorithmId)cert.get(X509CertImpl.SIG_ALG);
  info.set(CertificateAlgorithmId.NAME + "." + CertificateAlgorithmId.ALGORITHM, algo);
  cert = new X509CertImpl(info);
  cert.sign(privkey, algorithm);
  return cert;
}   

Answer 2

签署证书的能力不是标准 Java 库或扩展的一部分。

很多需要自己做的代码是核心的一部分。有一些类可以编码和解码 X.500 名称、X.509 证书扩展、各种算法的公钥，当然还有实际执行数字签名的类。

自己实现这一点并非易事，但这绝对是可行的——我第一次制作证书签名的工作原型时可能花了 4 到 5 天。这对我来说是一个很棒的学习练习，但是当有免费可用的可用库时，很难证明这笔费用是合理的。

Answer 3

import sun.security.x509.*;

import java.security.cert.*;
import java.security.*;
import java.math.BigInteger;
import java.security.cert.Certificate;
import java.util.Date;
import java.io.IOException;

public class Example {
    /**
     * Create a self-signed X.509 Example
     *
     * @param dn        the X.509 Distinguished Name, eg "CN=Test, L=London, C=GB"
     * @param pair      the KeyPair
     * @param days      how many days from now the Example is valid for
     * @param algorithm the signing algorithm, eg "SHA1withRSA"
     */
    public X509Certificate generateCertificate(String dn, KeyPair pair, int days, String algorithm)
            throws GeneralSecurityException, IOException {
        PrivateKey privkey = pair.getPrivate();
        X509CertInfo info = new X509CertInfo();
        Date from = new Date();
        Date to = new Date(from.getTime() + days * 86400000l);
        CertificateValidity interval = new CertificateValidity(from, to);
        BigInteger sn = new BigInteger(64, new SecureRandom());
        X500Name owner = new X500Name(dn);

        info.set(X509CertInfo.VALIDITY, interval);
        info.set(X509CertInfo.SERIAL_NUMBER, new CertificateSerialNumber(sn));
        info.set(X509CertInfo.SUBJECT, owner);
        info.set(X509CertInfo.ISSUER, owner);
        info.set(X509CertInfo.KEY, new CertificateX509Key(pair.getPublic()));
        info.set(X509CertInfo.VERSION, new CertificateVersion(CertificateVersion.V3));
        AlgorithmId algo = new AlgorithmId(AlgorithmId.md5WithRSAEncryption_oid);
        info.set(X509CertInfo.ALGORITHM_ID, new CertificateAlgorithmId(algo));

        // Sign the cert to identify the algorithm that's used.
        X509CertImpl cert = new X509CertImpl(info);
        cert.sign(privkey, algorithm);

        // Update the algorith, and resign.
        algo = (AlgorithmId) cert.get(X509CertImpl.SIG_ALG);
        info.set(CertificateAlgorithmId.NAME + "." + CertificateAlgorithmId.ALGORITHM, algo);
        cert = new X509CertImpl(info);
        cert.sign(privkey, algorithm);
        return cert;
    }

    public static void main (String[] argv) throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        Example example = new Example();
        String distinguishedName = "CN=Test, L=London, C=GB";
        Certificate certificate = example.generateCertificateOriginal(distinguishedName, keyPair, 365, "SHA256withRSA");
        System.out.println("it worked!");
    }
}

我喜欢 vbence 的回答，但我不断收到以下异常：

java.security.cert.CertificateException：主题类类型无效。

经过多次尝试找出 是一个有效的主题类后，我发现 X509CerInfo 想要一个 X500Name 的实例。

1 info.set(X509CertInfo.SERIAL_NUMBER, new CertificateSerialNumber(sn));
2 info.set(X509CertInfo.SUBJECT, new CertificateSubjectName(owner));
3 info.set(X509CertInfo.ISSUER, new CertificateIssuerName(owner));
4 info.set(X509CertInfo.KEY, new CertificateX509Key(pair.getPublic()));

所以需要将第 2 行和第 3 行更改为

2 info.set(X509CertInfo.SUBJECT, owner);
3 info.set(X509CertInfo.ISSUER, owner);

Answer 4

JRE 中提供了制作自签名证书的所有基本组件（签名、X509 编码等）。与 BC 不同，Sun 的 JCE 不提供任何公开调用来签署证书。但是，所有功能都在 Keytool 中可用。您可以简单地从 keytool 复制代码来执行此操作。你需要复制的方法是doSelfCert()。

Answer 5

取决于您到底想做什么（可能还有您对“Sanely”的定义）。正如ZZ Coder所指出的，您可以通过复制keytool直接创建自签名证书。但我不相信您可以使用标准 JCE 创建 PKCS10 证书请求对象，如果您想创建标准 CA 签名的 EEC，您可能需要这样做。