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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

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 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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import java.security.interfaces.RSAPrivateKey;

import java.security.interfaces.RSAPublicKey;

import java.util.stream.IntStream;

import static javax.crypto.Cipher.PRIVATE_KEY;

import static javax.crypto.Cipher.PUBLIC_KEY;

/**

 * @test

 * @summary Create a signature for RSA and get its signed data. re-initiate

 *          the signature with the public key. The signature can be verified

 *          by acquired signed data.

 * @run main SignatureTest 512

 * @run main SignatureTest 768

 * @run main SignatureTest 1024

 * @run main SignatureTest 2048

 * @run main/timeout=240 SignatureTest 4096

 * @run main/timeout=240 SignatureTest 5120

 */

public class SignatureTest {

    /**

     * ALGORITHM name, fixed as RSA.

     */

    private static final String KEYALG = "RSA";

    /**

     * JDK default RSA Provider.

     */

    private static final String PROVIDER = "SunRsaSign";

    /**

     * How much times signature updated.

     */

    private static final int UPDATE_TIMES_FIFTY = 50;

    /**

     * How much times signature initial updated.

     */

    private static final int UPDATE_TIMES_HUNDRED = 100;

        byte[] data = new byte[100];

        IntStream.range(0, data.length).forEach(j -> {

            data[j] = (byte) j;

        });

        // create a key pair

        Key[] privs = manipulateKey(PRIVATE_KEY, kpair.getPrivate());

        Key[] pubs = manipulateKey(PUBLIC_KEY, kpair.getPublic());

        // For signature algorithm, create and verify a signature

        Arrays.stream(privs).forEach(priv

                -> Arrays.stream(pubs).forEach(pub

            try {

                checkSignature(data, (PublicKey) pub, (PrivateKey) priv,

            } catch (NoSuchAlgorithmException | InvalidKeyException |

                throw new RuntimeException(ex);

            }

        }

        )));

    }

    private static KeyPair generateKeys(String keyalg, int size)

            throws NoSuchAlgorithmException {

        KeyPairGenerator kpg = KeyPairGenerator.getInstance(keyalg);

        kpg.initialize(size);

        return kpg.generateKeyPair();

    }

    private static Key[] manipulateKey(int type, Key key)

            throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchProviderException {

        KeyFactory kf = KeyFactory.getInstance(KEYALG, PROVIDER);

        switch (type) {

            case PUBLIC_KEY:

                try {

                    kf.getKeySpec(key, RSAPrivateKeySpec.class);

                    throw new RuntimeException("Expected InvalidKeySpecException "

                            + "not thrown");

                } catch (InvalidKeySpecException expected) {

                }

                return new Key[]{

                    kf.generatePublic(kf.getKeySpec(key, RSAPublicKeySpec.class)),

                    kf.generatePublic(new X509EncodedKeySpec(key.getEncoded())),

                    kf.generatePublic(new RSAPublicKeySpec(

                    ((RSAPublicKey) key).getModulus(),

                    ((RSAPublicKey) key).getPublicExponent()))

                };

            case PRIVATE_KEY:

                try {

                    kf.getKeySpec(key, RSAPublicKeySpec.class);

                    throw new RuntimeException("Expected InvalidKeySpecException"

                            + " not thrown");

                } catch (InvalidKeySpecException expected) {

                }

                return new Key[]{

                    kf.generatePrivate(kf.getKeySpec(key,

                    RSAPrivateKeySpec.class)),

                    kf.generatePrivate(new PKCS8EncodedKeySpec(

                    key.getEncoded())),

                    kf.generatePrivate(new RSAPrivateKeySpec(((RSAPrivateKey) key).getModulus(),

                    ((RSAPrivateKey) key).getPrivateExponent()))

                };

        }

        throw new RuntimeException("We shouldn't reach here");

    }

    private static void checkSignature(byte[] data, PublicKey pub,

        sig.initSign(priv);

        for (int i = 0; i < UPDATE_TIMES_HUNDRED; i++) {

            sig.update(data);

        }

        byte[] signedData = sig.sign();

        // Make sure signature verifies with original data

        sig.initVerify(pub);

        for (int i = 0; i < UPDATE_TIMES_HUNDRED; i++) {

            sig.update(data);

        }

        if (!sig.verify(signedData)) {

                    + " signature");

        }

        // Make sure signature does NOT verify when the original data

        // has changed

        sig.initVerify(pub);

        for (int i = 0; i < UPDATE_TIMES_FIFTY; i++) {

            sig.update(data);

        }

        if (sig.verify(signedData)) {

                    + " signature");

        }

    }

}