Java by API/java.security.cert/CertificateFactory

CertificateFactory: generateCertificate(InputStream inStream) throws CertificateException

   <source lang="java">
 

import java.io.FileInputStream; import java.security.Principal; import java.security.cert.Certificate; import java.security.cert.CertificateFactory; import java.security.cert.X509Certificate; public class Main {

 public static void main(String args[]) throws Exception {
   Certificate[] certpath = new Certificate[args.length];
   CertificateFactory cf = CertificateFactory.getInstance("X.509");
   for (int i = 0; i < args.length; i++) {
     FileInputStream in = new FileInputStream(args[i]);
     certpath[i] = cf.generateCertificate(in);
   }
   for (int i = 0; i < certpath.length - 1; i++) {
     Principal issuer = ((X509Certificate) certpath[i]).getIssuerDN();
     Principal subject = ((X509Certificate) certpath[i + 1]).getSubjectDN();
     if (!issuer.equals(subject)) {
       System.out.println("in " + i + " issuer is " + issuer);
       System.out.println("But in " + (i + 1));
       System.out.println("subject is " + subject);
       break;
     }
   }
 }

}

 </source>
   
  
 
  

CertificateFactory: generateCertPath(List<? extends Certificate> certificates) throws CertificateException

   <source lang="java">
 

import java.io.FileOutputStream; import java.io.ObjectOutputStream; import java.security.cert.CertPath; import java.security.cert.CertificateFactory; import java.util.ArrayList; import java.util.List; import javax.net.ssl.HttpsURLConnection; import javax.net.ssl.SSLSession; import javax.net.ssl.SSLSocket; import javax.net.ssl.SSLSocketFactory; public class Main {

 public static void main(String args[]) throws Exception {
   SSLSocketFactory factory = HttpsURLConnection.getDefaultSSLSocketFactory();
   SSLSocket socket = (SSLSocket) factory.createSocket("127.0.0.1", 9999);
   socket.startHandshake();
   SSLSession session = socket.getSession();
   java.security.cert.Certificate[] servercerts = session.getPeerCertificates();
   List mylist = new ArrayList();
   for (int i = 0; i < servercerts.length; i++) {
     mylist.add(servercerts[i]);
   }
   CertificateFactory cf = CertificateFactory.getInstance("X.509");
   CertPath cp = cf.generateCertPath(mylist);
   FileOutputStream f = new FileOutputStream("CertPath.dat");
   ObjectOutputStream b = new ObjectOutputStream(f);
   b.writeObject(cp);
 }

}

 </source>
   
  
 
  

CertificateFactory: getInstance(String type) throws CertificateException

   <source lang="java">
 

import java.io.FileInputStream; import java.security.Principal; import java.security.cert.Certificate; import java.security.cert.CertificateFactory; import java.security.cert.X509Certificate; public class Main {

 public static void main(String args[]) throws Exception {
   Certificate[] certpath = new Certificate[args.length];
   CertificateFactory cf = CertificateFactory.getInstance("X.509");
   for (int i = 0; i < args.length; i++) {
     FileInputStream in = new FileInputStream(args[i]);
     certpath[i] = cf.generateCertificate(in);
   }
   for (int i = 0; i < certpath.length - 1; i++) {
     Principal issuer = ((X509Certificate) certpath[i]).getIssuerDN();
     Principal subject = ((X509Certificate) certpath[i + 1]).getSubjectDN();
     if (!issuer.equals(subject)) {
       System.out.println("in " + i + " issuer is " + issuer);
       System.out.println("But in " + (i + 1));
       System.out.println("subject is " + subject);
       break;
     }
   }
 }

}

 </source>