Example usage for java.security.spec DSAPublicKeySpec getQ

Introduction

In this page you can find the example usage for java.security.spec DSAPublicKeySpec getQ.

Prototype

public BigInteger getQ() 

Source Link

Document

Returns the sub-prime q .

Usage

From source file:MainClass.java

public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeySpecException {
    KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");
    kpg.initialize(512);/*from w  w w. j  a  v  a2 s.  c  o  m*/
    KeyPair keys = kpg.genKeyPair();
    PrivateKey priKey = keys.getPrivate();
    PublicKey pubKey = keys.getPublic();
    KeyFactory kf = KeyFactory.getInstance("DSA");
    DSAPrivateKeySpec dsaPriKeySpec = (DSAPrivateKeySpec) kf.getKeySpec(priKey, DSAPrivateKeySpec.class);
    DSAPublicKeySpec dsaPubKeySpec = (DSAPublicKeySpec) kf.getKeySpec(pubKey, DSAPublicKeySpec.class);
    System.out.println("\nDSA Private Key");
    System.out.println("\nx = " + dsaPriKeySpec.getX());
    System.out.println("\nDSA Public Key");
    System.out.println("\ng = " + dsaPubKeySpec.getG());
    System.out.println("\np = " + dsaPubKeySpec.getP());
    System.out.println("\nq = " + dsaPubKeySpec.getQ());
    System.out.println("\ny = " + dsaPubKeySpec.getY());
}

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From source file:MainClass.java

public static void main(String args[]) throws Exception {
    KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA");
    SecureRandom random = SecureRandom.getInstance("SHA1PRNG", "SUN");
    random.setSeed(101L);//from w w w  .  j  a  va2  s.  co  m
    keyGen.initialize(1024, random);
    KeyPair keypair = keyGen.generateKeyPair();

    KeyFactory kfactory = KeyFactory.getInstance("DSA");

    DSAPublicKeySpec kspec = (DSAPublicKeySpec) kfactory.getKeySpec(keypair.getPublic(),
            DSAPublicKeySpec.class);

    System.out.println(keypair.getPublic());
    FileOutputStream fos = new FileOutputStream("publicKeys");
    ObjectOutputStream oos = new ObjectOutputStream(fos);

    oos.writeObject(kspec.getY());
    oos.writeObject(kspec.getP());
    oos.writeObject(kspec.getQ());
    oos.writeObject(kspec.getG());

    FileInputStream fin = new FileInputStream("publicKeys");
    ObjectInputStream ois = new ObjectInputStream(fin);

    BigInteger Y = (BigInteger) ois.readObject();
    BigInteger P = (BigInteger) ois.readObject();
    BigInteger Q = (BigInteger) ois.readObject();
    BigInteger G = (BigInteger) ois.readObject();

    DSAPublicKeySpec keyspec = new DSAPublicKeySpec(Y, P, Q, G);
    PublicKey pkey = kfactory.generatePublic(keyspec);
    System.out.println(pkey);
}

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