Java Tutorial/Security/Public Key Infrastructure X.509

Getting the Subject and Issuer Distinguished Names of an X509 Certificate

   <source lang="java">

import java.io.FileInputStream; import java.security.KeyStore; import java.security.Principal; import java.security.cert.X509Certificate; import java.util.Enumeration; public class Main {

 public static void main(String[] argv) throws Exception {
   FileInputStream is = new FileInputStream("your.keystore");
   KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
   keystore.load(is, "my-keystore-password".toCharArray());
   Enumeration e = keystore.aliases();
   for (; e.hasMoreElements();) {
     String alias = (String) e.nextElement();
     java.security.cert.Certificate cert = keystore.getCertificate(alias);
     if (cert instanceof X509Certificate) {
       X509Certificate x509cert = (X509Certificate) cert;
       // Get subject
       Principal principal = x509cert.getSubjectDN();
       String subjectDn = principal.getName();
       // Get issuer
       principal = x509cert.getIssuerDN();
       String issuerDn = principal.getName();
     }
   }
 }

}</source>

Listing the Most-Trusted Certificate Authorities (CA) in a Key Store

   <source lang="java">

import java.io.File; import java.io.FileInputStream; import java.security.KeyStore; import java.security.cert.PKIXParameters; import java.security.cert.TrustAnchor; import java.security.cert.X509Certificate; import java.util.Iterator; public class Main {

 public static void main(String[] argv) throws Exception {
   String filename = System.getProperty("java.home")
       + "/lib/security/cacerts".replace("/", File.separatorChar);
   FileInputStream is = new FileInputStream(filename);
   KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
   String password = "password";
   keystore.load(is, password.toCharArray());
   PKIXParameters params = new PKIXParameters(keystore);
   Iterator it = params.getTrustAnchors().iterator();
   for (; it.hasNext();) {
     TrustAnchor ta = (TrustAnchor) it.next();
     X509Certificate cert = ta.getTrustedCert();
     System.out.println(cert.getSigAlgName());
   }
 }

}</source>

PKIX Demo

   <source lang="java">

import java.io.FileInputStream; import java.math.BigInteger; import java.security.KeyStore; import java.security.PublicKey; import java.security.cert.CertPath; import java.security.cert.CertPathValidator; import java.security.cert.Certificate; import java.security.cert.CertificateFactory; import java.security.cert.PKIXCertPathValidatorResult; import java.security.cert.PKIXParameters; import java.security.cert.TrustAnchor; import java.security.cert.X509Certificate; import java.util.ArrayList; import java.util.List; public class MainClass {

 public static void main(String args[]) throws Exception {
   CertificateFactory cf = CertificateFactory.getInstance("X.509");
   List mylist = new ArrayList();
   FileInputStream in = new FileInputStream(args[0]);
   Certificate c = cf.generateCertificate(in);
   mylist.add(c);
   CertPath cp = cf.generateCertPath(mylist);
   FileInputStream kin = new FileInputStream(args[0]);
   KeyStore ks = KeyStore.getInstance("JKS");
   ks.load(kin, args[1].toCharArray());
   PKIXParameters params = new PKIXParameters(ks);
   params.setRevocationEnabled(false);
   CertPathValidator cpv = CertPathValidator.getInstance("PKIX");
   PKIXCertPathValidatorResult result = (PKIXCertPathValidatorResult) cpv.validate(cp, params);
   PublicKey pbk = result.getPublicKey();
   byte[] pkenc = pbk.getEncoded();
   BigInteger pk = new BigInteger(pkenc);
   System.out.println(pk.toString(16));
   TrustAnchor anc = result.getTrustAnchor();
   X509Certificate xc = anc.getTrustedCert();
   System.out.println(xc.getSubjectDN());
   System.out.println(xc.getIssuerDN());
 }

}</source>