Java Key Public getPublicKey(final String algorithm, final File publicKeyFile)

Description

get Public Key

License

Open Source License

Declaration

private static PublicKey getPublicKey(final String algorithm, final File publicKeyFile) 

Method Source Code

//package com.java2s;
/**// w ww .  ja v a2s .  co m
 * Copyright (C) 2010-2016 Structr GmbH
 *
 * This file is part of Structr <http://structr.org>.
 *
 * Structr is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * Structr 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Structr.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.io.File;

import java.nio.file.Files;
import java.security.KeyFactory;

import java.security.PublicKey;

import java.security.spec.X509EncodedKeySpec;

public class Main {
    private static PublicKey getPublicKey(final String algorithm, final File publicKeyFile) {
        return getPublicKeyFromBytes(algorithm, readBytes(publicKeyFile));
    }

    private static PublicKey getPublicKeyFromBytes(final String algorithm, final byte[] publicKeyBytes) {

        try {

            final KeyFactory keyFactory = KeyFactory.getInstance(algorithm);
            final X509EncodedKeySpec spec = new X509EncodedKeySpec(publicKeyBytes);

            return keyFactory.generatePublic(spec);

        } catch (Throwable t) {
            t.printStackTrace();
        }

        return null;
    }

    private static byte[] readBytes(final File file) {

        try {

            return Files.readAllBytes(file.toPath());

        } catch (Throwable t) {
            t.printStackTrace();
        }

        return null;
    }
}

Related

1. getPublicKey(BigInteger modulus, BigInteger exponent)
2. getPublicKey(byte[] der)
3. getPublicKey(byte[] keyBytes, String algorithm)
4. getPublicKey(final byte[] keyData)
5. getPublicKey(final byte[] modulus, final byte[] exponent)
6. getPublicKey(KeyPair keyPair)
7. getPublicKey(KeyPair keyPair)
8. getPublicKey(KeyPair kp)
9. getPublicKey(KeyStore keyStore, String alias)