Java by API/java.security.cert/X509Certificate

X509Certificate: getIssuerDN()

 
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.security.Principal;
import java.security.cert.X509Certificate;
import javax.net.ssl.SSLPeerUnverifiedException;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
public class MainClass {
  public static void main(String[] args) throws Exception {
    SSLSocketFactory factory = (SSLSocketFactory) SSLSocketFactory.getDefault();
    String hostName = "hostName";
    String fileName = "fileName";
    SSLSocket sslsock = (SSLSocket) factory.createSocket(hostName, 443);
    SSLSession session = sslsock.getSession();
    X509Certificate cert;
    try {
      cert = (X509Certificate) session.getPeerCertificates()[0];
    } catch (SSLPeerUnverifiedException e) {
      System.err.println(session.getPeerHost() + " did not present a valid certificate.");
      return;
    }
    System.out.println(session.getPeerHost() + " has presented a certificate belonging to:");
    Principal p = cert.getSubjectDN();
    System.out.println("\t[" + p.getName() + "]");
    System.out.println("The certificate bears the valid signature of:");
    System.out.println("\t[" + cert.getIssuerDN().getName() + "]");
    System.out.print("Do you trust this certificate (y/n)? ");
    System.out.flush();
    BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
    if (Character.toLowerCase(console.readLine().charAt(0)) != "y")
      return;
    PrintWriter out = new PrintWriter(sslsock.getOutputStream());
    out.print("GET " + fileName + " HTTP/1.0\r\n\r\n");
    out.flush();
    BufferedReader in = new BufferedReader(new InputStreamReader(sslsock.getInputStream()));
    String line;
    while ((line = in.readLine()) != null)
      System.out.println(line);
    sslsock.close();
  }
}

X509Certificate: getNotBefore()

  
import java.io.FileInputStream;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
public class MainClass {
  public static void main(String args[]) throws Exception {
    FileInputStream fr = new FileInputStream("sdo.cer");
    CertificateFactory cf = CertificateFactory.getInstance("X509");
    X509Certificate c = (X509Certificate) cf.generateCertificate(fr);
    System.out.println("\tCertificate for: " + c.getSubjectDN());
    System.out.println("\tCertificate issued by: " + c.getIssuerDN());
    System.out.println("\tThe certificate is valid from " + c.getNotBefore() + " to "
        + c.getNotAfter());
    System.out.println("\tCertificate SN# " + c.getSerialNumber());
    System.out.println("\tGenerated with " + c.getSigAlgName());
  }
}

X509Certificate: getSerialNumber()

  
import java.io.FileInputStream;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
public class MainClass {
  public static void main(String args[]) throws Exception {
    FileInputStream fr = new FileInputStream("sdo.cer");
    CertificateFactory cf = CertificateFactory.getInstance("X509");
    X509Certificate c = (X509Certificate) cf.generateCertificate(fr);
    System.out.println("\tCertificate for: " + c.getSubjectDN());
    System.out.println("\tCertificate issued by: " + c.getIssuerDN());
    System.out.println("\tThe certificate is valid from " + c.getNotBefore() + " to "
        + c.getNotAfter());
    System.out.println("\tCertificate SN# " + c.getSerialNumber());
    System.out.println("\tGenerated with " + c.getSigAlgName());
  }
}

X509Certificate: getSigAlgName()

  
import java.io.FileInputStream;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
public class MainClass {
  public static void main(String args[]) throws Exception {
    FileInputStream fr = new FileInputStream("sdo.cer");
    CertificateFactory cf = CertificateFactory.getInstance("X509");
    X509Certificate c = (X509Certificate) cf.generateCertificate(fr);
    System.out.println("\tCertificate for: " + c.getSubjectDN());
    System.out.println("\tCertificate issued by: " + c.getIssuerDN());
    System.out.println("\tThe certificate is valid from " + c.getNotBefore() + " to "
        + c.getNotAfter());
    System.out.println("\tCertificate SN# " + c.getSerialNumber());
    System.out.println("\tGenerated with " + c.getSigAlgName());
  }
}

X509Certificate: getSubjectDN()

 
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.security.Principal;
import java.security.cert.X509Certificate;
import javax.net.ssl.SSLPeerUnverifiedException;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
public class MainClass {
  public static void main(String[] args) throws Exception {
    SSLSocketFactory factory = (SSLSocketFactory) SSLSocketFactory.getDefault();
    String hostName = "hostName";
    String fileName = "fileName";
    SSLSocket sslsock = (SSLSocket) factory.createSocket(hostName, 443);
    SSLSession session = sslsock.getSession();
    X509Certificate cert;
    try {
      cert = (X509Certificate) session.getPeerCertificates()[0];
    } catch (SSLPeerUnverifiedException e) {
      System.err.println(session.getPeerHost() + " did not present a valid certificate.");
      return;
    }
    System.out.println(session.getPeerHost() + " has presented a certificate belonging to:");
    Principal p = cert.getSubjectDN();
    System.out.println("\t[" + p.getName() + "]");
    System.out.println("The certificate bears the valid signature of:");
    System.out.println("\t[" + cert.getIssuerDN().getName() + "]");
    System.out.print("Do you trust this certificate (y/n)? ");
    System.out.flush();
    BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
    if (Character.toLowerCase(console.readLine().charAt(0)) != "y")
      return;
    PrintWriter out = new PrintWriter(sslsock.getOutputStream());
    out.print("GET " + fileName + " HTTP/1.0\r\n\r\n");
    out.flush();
    BufferedReader in = new BufferedReader(new InputStreamReader(sslsock.getInputStream()));
    String line;
    while ((line = in.readLine()) != null)
      System.out.println(line);
    sslsock.close();
  }
}