How To Read a Websites Certificate

Question

I have used JSSE to read web pages from SSL websites. Is there a way I can use JSSE to read the public information in a website's certificate? What I need to read is how long the website's certifate is valid for. I can view these dates in a website's certificate using a broswer, but I need to read it in my java program.

Answer 1

I want to read the certificate validity from a web site but the code is failing during the startHandShake().I am getting a the following exception when I tried to connect to the ssl port using the code below. please help
javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: Couldn't find trusted certificate
     at com.sun.net.ssl.internal.ssl.BaseSSLSocketImpl.a(DashoA6275)
     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.a(DashoA6275)
     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.a(DashoA6275)
     at com.sun.net.ssl.internal.ssl.SunJSSE_az.a(DashoA6275)
     at com.sun.net.ssl.internal.ssl.SunJSSE_az.a(DashoA6275)
     at com.sun.net.ssl.internal.ssl.SunJSSE_ax.a(DashoA6275)
     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.a(DashoA6275)
     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.j(DashoA6275)
     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(DashoA6275)
     at Certificate.main(Certificate.java:37)
Caused by: java.security.cert.CertificateException: Couldn't find trusted certificate
     at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.a(DashoA6275)
     at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(DashoA6275)
     at com.sun.net.ssl.internal.ssl.JsseX509TrustManager.checkServerTrusted(DashoA6275)
     ... 7 more
The Code is as follows.
import java.net.*;
import java.io.*;
import java.security.*;
import java.security.Security;
import java.security.KeyStore;
import java.security.cert.X509Certificate;
import javax.net.*;
import javax.net.SocketFactory;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.*;
import java.util.*;
public class Certificate {
     public static void main(String[] args) {
          SSLSocketFactory factory = HttpsURLConnection.getDefaultSSLSocketFactory();
          //SSLSocket socket = (SSLSocket)factory.createSocket(host, port);
          SSLSocket socket = null;
          try{
          socket = (SSLSocket)factory.createSocket("xx.xx.xx.xx", 50000);
          //Connect to the server
          socket.startHandshake();
          catch(Exception eh){
               try{
                    socket.close();
               }catch(Exception eio)
                    eio.printStackTrace();
               eh.printStackTrace();
               System.exit(1);
          SSLSession session = socket.getSession();
          javax.security.cert.X509Certificate certchain[] = null;
          certchain = new javax.security.cert.X509Certificate[1];
          //- get all the certs in the chain for this server
          try {
               certchain = session.getPeerCertificateChain();
          catch(Exception es){
               System.err.println("Error");
          //- follow cert chain, look at each cert
          for (int ii = 0; ii < certchain.length; ii++) {
               System.out.println( "---- Certchain Cert number: " + ii + " ----");
               // Check validity
               String validity = "Cert is valid";
               try { certchain[ii].checkValidity();
               } catch (javax.security.cert.CertificateExpiredException ex ) {
                    System.out.println( "Certificate has expired!" );
                    validity = "Certificate Expired!";
               } catch (javax.security.cert.CertificateNotYetValidException ex ) {
                    System.out.println( "Certificate is not yet valid!" );
                    validity = "Certificate Not Yet Valid";
               String subjectDN = certchain[ii].getSubjectDN().getName();
               String issuerDN = certchain[ii].getIssuerDN().getName();
               Date notAfter = certchain[ii].getNotAfter();
               Date notBefore = certchain[ii].getNotBefore();
               int version = certchain[ii].getVersion();
               String peerHost = session.getPeerHost();
               String sessionProto = session.getProtocol();
               String cipherSuite = session.getCipherSuite();
               boolean needClientAuth = socket.getNeedClientAuth();
               String stringImageOfCert = certchain[ii].toString();
               System.out.println("IssuerDN ===== " + issuerDN);
               System.out.println("Validity ===== " + validity);
               System.out.println("NotAfter ===== " + notAfter.toString());
               System.out.println("NotBefore ==== " + notBefore.toString());
               System.out.println("Version ===== " + version);
               System.out.println("SubjectDN === " + subjectDN);
               System.out.println("PeerHost ==== " + peerHost);
               System.out.println("SessionProto = " + sessionProto);
               System.out.println("CipherSuite == " + cipherSuite);
               System.out.println("NeedClntAuth = " + needClientAuth);
               System.out.println("StringImageOfCert = "+ stringImageOfCert);          
          try {
               socket.close();
          }catch (Exception ess) {}