Example usage for java.security Signature getInstance

Introduction

In this page you can find the example usage for java.security Signature getInstance.

Prototype

public static Signature getInstance(String algorithm) throws NoSuchAlgorithmException 

Source Link

Document

Returns a Signature object that implements the specified signature algorithm.

Usage

From source file:Main.java

public static void main(String[] args) throws Exception {
    KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
    kpg.initialize(1024);/*w ww  .j a v a2 s.  co  m*/
    KeyPair keyPair = kpg.genKeyPair();

    byte[] data = "test".getBytes("UTF8");

    Signature sig = Signature.getInstance("MD5WithRSA");
    sig.initSign(keyPair.getPrivate());
    sig.update(data);
    byte[] signatureBytes = sig.sign();
    System.out.println("Singature:" + new BASE64Encoder().encode(signatureBytes));

    sig.initVerify(keyPair.getPublic());
    sig.update(data);

    System.out.println(sig.verify(signatureBytes));
}

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From source file:MainClass.java

public static void main(String[] args) throws Exception {
    String alg = "DSA";
    KeyPairGenerator kg = KeyPairGenerator.getInstance(alg);
    KeyPair keyPair = kg.genKeyPair();

    Vector v = new Vector();
    v.add("This is a test!");
    Signature sign = Signature.getInstance(alg);
    SignedObject so = new SignedObject(v, keyPair.getPrivate(), sign);
    System.out.println(so.verify(keyPair.getPublic(), sign));
}

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From source file:Main.java

public static void main(String[] argv) throws Exception {
    KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA");
    keyGen.initialize(1024);//from   w  w  w. ja  va 2s .c o m
    KeyPair keypair = keyGen.genKeyPair();
    PrivateKey privateKey = keypair.getPrivate();
    PublicKey publicKey = keypair.getPublic();

    Serializable o = new MyClass();
    Signature sig = Signature.getInstance(privateKey.getAlgorithm());
    SignedObject so = new SignedObject(o, privateKey, sig);

    sig = Signature.getInstance(publicKey.getAlgorithm());
    boolean b = so.verify(publicKey, sig);
    o = (MyClass) so.getObject();
}

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From source file:Main.java

public static void main(String[] argv) throws Exception {
    KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA");
    keyGen.initialize(1024);/*from w w w .  j a  v a2 s .  c o  m*/
    KeyPair keypair = keyGen.genKeyPair();
    DSAPrivateKey privateKey = (DSAPrivateKey) keypair.getPrivate();
    DSAPublicKey publicKey = (DSAPublicKey) keypair.getPublic();

    DSAParams dsaParams = privateKey.getParams();
    BigInteger p = dsaParams.getP();
    BigInteger q = dsaParams.getQ();
    BigInteger g = dsaParams.getG();
    BigInteger x = privateKey.getX();
    BigInteger y = publicKey.getY();

    // Create the DSA key factory
    KeyFactory keyFactory = KeyFactory.getInstance("DSA");
    // Create the DSA private key
    KeySpec privateKeySpec = new DSAPrivateKeySpec(x, p, q, g);
    PrivateKey privateKey1 = keyFactory.generatePrivate(privateKeySpec);

    byte[] buffer = new byte[1024];

    Signature sig = Signature.getInstance(privateKey1.getAlgorithm());
    sig.initSign(privateKey1);
    sig.update(buffer, 0, buffer.length);
}

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From source file:com.threerings.getdown.tools.AppletParamSigner.java

public static void main(String[] args) {
    try {// ww w .ja  v  a  2s .  c  o m
        if (args.length != 7) {
            System.err
                    .println("AppletParamSigner keystore storepass alias keypass " + "appbase appname imgpath");
            System.exit(255);
        }

        String keystore = args[0];
        String storepass = args[1];
        String alias = args[2];
        String keypass = args[3];
        String appbase = args[4];
        String appname = args[5];
        String imgpath = args[6];
        String params = appbase + appname + imgpath;

        KeyStore store = KeyStore.getInstance("JKS");
        store.load(new BufferedInputStream(new FileInputStream(keystore)), storepass.toCharArray());
        PrivateKey key = (PrivateKey) store.getKey(alias, keypass.toCharArray());
        Signature sig = Signature.getInstance("SHA1withRSA");
        sig.initSign(key);
        sig.update(params.getBytes());
        String signed = new String(Base64.encodeBase64(sig.sign()));
        System.out.println("<param name=\"appbase\" value=\"" + appbase + "\" />");
        System.out.println("<param name=\"appname\" value=\"" + appname + "\" />");
        System.out.println("<param name=\"bgimage\" value=\"" + imgpath + "\" />");
        System.out.println("<param name=\"signature\" value=\"" + signed + "\" />");

    } catch (Exception e) {
        System.err.println("Failed to produce signature.");
        e.printStackTrace();
    }
}

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From source file:Main.java

public static void main(String[] argv) throws Exception {
    KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA");
    keyGen.initialize(1024);//  w  w w.  j  av  a  2s.co  m
    KeyPair keypair = keyGen.genKeyPair();
    DSAPrivateKey privateKey = (DSAPrivateKey) keypair.getPrivate();
    DSAPublicKey publicKey = (DSAPublicKey) keypair.getPublic();

    DSAParams dsaParams = privateKey.getParams();
    BigInteger p = dsaParams.getP();
    BigInteger q = dsaParams.getQ();
    BigInteger g = dsaParams.getG();
    BigInteger x = privateKey.getX();
    BigInteger y = publicKey.getY();

    KeyFactory keyFactory = KeyFactory.getInstance("DSA");
    KeySpec publicKeySpec = new DSAPublicKeySpec(y, p, q, g);
    PublicKey publicKey1 = keyFactory.generatePublic(publicKeySpec);
    KeySpec privateKeySpec = new DSAPrivateKeySpec(x, p, q, g);
    PrivateKey privateKey1 = keyFactory.generatePrivate(privateKeySpec);

    byte[] buffer = new byte[1024];

    Signature sig = Signature.getInstance(privateKey1.getAlgorithm());
    sig.initSign(privateKey1);
    sig.update(buffer, 0, buffer.length);

    byte[] signature = sig.sign();

    sig = Signature.getInstance(publicKey1.getAlgorithm());
    sig.initVerify(publicKey1);
    sig.update(buffer, 0, buffer.length);
    sig.verify(signature);

}

---

From source file:SignatureTest.java

public static void main(String[] args) {
    try {/*from ww  w.j av  a  2 s . c o  m*/
        if (args[0].equals("-genkeypair")) {
            KeyPairGenerator pairgen = KeyPairGenerator.getInstance("DSA");
            SecureRandom random = new SecureRandom();
            pairgen.initialize(KEYSIZE, random);
            KeyPair keyPair = pairgen.generateKeyPair();
            ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(args[1]));
            out.writeObject(keyPair.getPublic());
            out.close();
            out = new ObjectOutputStream(new FileOutputStream(args[2]));
            out.writeObject(keyPair.getPrivate());
            out.close();
        } else if (args[0].equals("-sign")) {
            ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[3]));
            PrivateKey privkey = (PrivateKey) keyIn.readObject();
            keyIn.close();

            Signature signalg = Signature.getInstance("DSA");
            signalg.initSign(privkey);

            File infile = new File(args[1]);
            InputStream in = new FileInputStream(infile);
            int length = (int) infile.length();
            byte[] message = new byte[length];
            in.read(message, 0, length);
            in.close();

            signalg.update(message);
            byte[] signature = signalg.sign();

            DataOutputStream out = new DataOutputStream(new FileOutputStream(args[2]));
            int signlength = signature.length;
            out.writeInt(signlength);
            out.write(signature, 0, signlength);
            out.write(message, 0, length);
            out.close();
        } else if (args[0].equals("-verify")) {
            ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[2]));
            PublicKey pubkey = (PublicKey) keyIn.readObject();
            keyIn.close();

            Signature verifyalg = Signature.getInstance("DSA");
            verifyalg.initVerify(pubkey);

            File infile = new File(args[1]);
            DataInputStream in = new DataInputStream(new FileInputStream(infile));
            int signlength = in.readInt();
            byte[] signature = new byte[signlength];
            in.read(signature, 0, signlength);

            int length = (int) infile.length() - signlength - 4;
            byte[] message = new byte[length];
            in.read(message, 0, length);
            in.close();

            verifyalg.update(message);
            if (!verifyalg.verify(signature))
                System.out.print("not ");
            System.out.println("verified");
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

---

From source file:testSig.java

public static void main(String[] args) {

    /* Test generating and verifying a DSA signature */

    try {/*from   ww  w  . j  ava2s . c  om*/

        /* generate a key pair */

        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA");
        keyGen.initialize(1024, new SecureRandom());
        KeyPair pair = keyGen.generateKeyPair();

        /*
         * create a Signature object to use for signing and verifying
         */

        Signature dsa = Signature.getInstance("SHA/DSA");

        /* initialize the Signature object for signing */

        PrivateKey priv = pair.getPrivate();

        dsa.initSign(priv);

        /* Update and sign the data */

        FileInputStream fis = new FileInputStream(args[0]);
        byte b;
        while (fis.available() != 0) {
            b = (byte) fis.read();
            dsa.update(b);
        }
        ;

        fis.close();

        /*
         * Now that all the data to be signed has been read in, sign it
         */
        byte[] sig = dsa.sign();

        /* Verify the signature */

        /* Initialize the Signature object for verification */
        PublicKey pub = pair.getPublic();
        dsa.initVerify(pub);

        /* Update and verify the data */

        fis = new FileInputStream(args[0]);
        while (fis.available() != 0) {
            b = (byte) fis.read();
            dsa.update(b);
        }
        ;

        fis.close();

        boolean verifies = dsa.verify(sig);

        System.out.println("signature verifies: " + verifies);

    } catch (Exception e) {
        System.err.println("Caught exception " + e.toString());
    }

}

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From source file:Main.java

static Signature getSignatureInstance(String algorithm) throws NoSuchAlgorithmException {
    return Signature.getInstance(algorithm);
}

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From source file:Main.java

static Signature createSignatureInstance(String sigName, String provider)
        throws NoSuchAlgorithmException, NoSuchProviderException {
    if (provider == null) {
        return Signature.getInstance(sigName);
    }/*  www  .  ja v a2s .  c  o  m*/

    return Signature.getInstance(sigName, provider);
}

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