Java 自签名证书和密钥库的使用答案

【问题标题】：Java self signed certificate and keystore usageJava 自签名证书和密钥库的使用
【发布时间】：2013-03-11 21:16:12
【问题描述】：

我需要根据公共证书创建公钥和私钥。我可以使用以下代码生成自签名证书...

    KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");  
    keyPairGenerator.initialize(1024);  
    KeyPair KPair = keyPairGenerator.generateKeyPair(); 
   PrivateKey privkey = KPair.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);

现在我需要使用密钥库或任何其他方式保存私钥和公钥，以便我可以检索那些用于签署任何文件或对象的密钥。我尝试使用简单的文件流，但它给了我错误，似乎它不是正确的方法。请指导我下一步该怎么做。我想使用证书和私钥来签署一些数据，我想保存它们以便我可以随时使用验证。

【问题讨论】：

标签： java x509certificate keystore pki

【解决方案1】：

我找到了答案

   private  void savePublicKeyToFile(String fileName,
                                BigInteger mod, BigInteger exp) throws IOException {
     ObjectOutputStream oout = new ObjectOutputStream(
             new BufferedOutputStream(new FileOutputStream(fileName)));
     try {
         oout.writeObject(mod);
         oout.writeObject(exp);
     } catch (Exception e) {
        // throw new SomeException(e);
     } finally {
         oout.close();
     }
 }

  private  void savePrivteKeyToFile(String fileName,
                                BigInteger mod, BigInteger PublicExponent, BigInteger PrivateExponent,
            BigInteger PrimeP, BigInteger PrimeQ,BigInteger PrimeExponentP,BigInteger PrimeExponentQ,
            BigInteger CrtCoefficient) throws IOException {
     ObjectOutputStream oout = new ObjectOutputStream(
             new BufferedOutputStream(new FileOutputStream(fileName)));
     try {
         oout.writeObject(mod);
         oout.writeObject(PublicExponent);
         oout.writeObject(PrivateExponent);
         oout.writeObject(PrimeP);
         oout.writeObject(PrimeQ);
         oout.writeObject(PrimeExponentP);
         oout.writeObject(PrimeExponentQ);
         oout.writeObject(CrtCoefficient);
     } catch (Exception e) {
        // throw new SomeException(e);
     } finally {
         oout.close();
     }
 }


     // To save in keystore here is the way


     Certificate [] certChain = new Certificate[1];
    certChain[0] = ca;
    String strAlias = "abcalias", strPassword="mypass";
    KeyStore keyStore = KeyStore.getInstance("jks");
    keyStore.load(null,strPassword.toCharArray());
    keyStore.setEntry(strAlias,
       new KeyStore.PrivateKeyEntry((PrivateKey) KPair.getPrivate(), certChain),
       new KeyStore.PasswordProtection(strPassword.toCharArray()));

    FileOutputStream fkey = new FileOutputStream(strFilePath+".keystore"); 
    keyStore.store(fkey, strPassword.toCharArray());
    fkey.close();

【讨论】：