de.alpharogroup.crypto.aes.HexDecryptor.java Source code

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Here is the source code for de.alpharogroup.crypto.aes.HexDecryptor.java

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/**
 * Copyright (C) 2007 Asterios Raptis
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package de.alpharogroup.crypto.aes;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

import lombok.AccessLevel;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import org.apache.commons.codec.DecoderException;

import de.alpharogroup.crypto.CryptConst;
import de.alpharogroup.crypto.algorithm.Algorithm;
import de.alpharogroup.crypto.interfaces.Decryptor;
import de.alpharogroup.crypto.simple.SimpleDecryptor;

/**
 * Instantiates a new hex decryptor.
 */
@NoArgsConstructor
public class HexDecryptor implements Decryptor {

    /**
     * The Cipher object.
     */
    @Getter
    @Setter
    private Cipher cipher = null;

    /**
     * The private key.
     */
    @Getter
    @Setter
    private String privateKey = null;

    /**
     * The flag initialized that indicates if the cypher is initialized for decryption.
     *
     * @return true, if is initialized
     */
    @Getter(value = AccessLevel.PRIVATE)
    private boolean initialized;

    /**
     * Constructor with a private key.
     *
     * @param privateKey
     *            The private key.
     */
    public HexDecryptor(final String privateKey) {
        this.setPrivateKey(privateKey);
    }

    /**
     * Decrypt the given encrypted String.
     * 
     * @param encypted
     *            The String to decrypt.
     * @return The decrypted String
     * 
     * @throws UnsupportedEncodingException
     *             is thrown by get the byte array of the private key String object fails.
     * @throws NoSuchAlgorithmException
     *             is thrown if instantiation of the cypher object fails.
     * @throws NoSuchPaddingException
     *             is thrown if instantiation of the cypher object fails.
     * @throws InvalidKeyException
     *             the invalid key exception is thrown if initialization of the cypher object fails.
     * @throws org.apache.commons.codec.DecoderException
     *             is thrown if an odd number or illegal of characters is supplied
     * @throws IllegalBlockSizeException
     *             is thrown if {@link Cipher#doFinal(byte[])} fails.
     * @throws BadPaddingException
     *             is thrown if {@link Cipher#doFinal(byte[])} fails.
     */
    @Override
    public String decrypt(final String encypted)
            throws InvalidKeyException, UnsupportedEncodingException, NoSuchAlgorithmException,
            NoSuchPaddingException, DecoderException, IllegalBlockSizeException, BadPaddingException {
        initialize();
        final byte[] dec = HexDump.decodeHex(encypted.toCharArray());
        final byte[] utf8 = this.cipher.doFinal(dec);
        return new String(utf8, "UTF-8");
    }

    /**
     * Initializes the {@link SimpleDecryptor} object.
     *
     * @throws UnsupportedEncodingException
     *             is thrown by get the byte array of the private key String object fails.
     * @throws NoSuchAlgorithmException
     *             is thrown if instantiation of the cypher object fails.
     * @throws NoSuchPaddingException
     *             is thrown if instantiation of the cypher object fails.
     * @throws InvalidKeyException
     *             the invalid key exception is thrown if initialization of the cypher object fails.
     */
    private void initialize() throws UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException,
            InvalidKeyException {
        if (!isInitialized()) {
            byte[] key;
            if (this.getPrivateKey() != null) {
                key = this.getPrivateKey().getBytes("UTF-8");
            } else {
                key = CryptConst.PRIVATE_KEY.getBytes("UTF-8");
            }
            final SecretKeySpec skeySpec = new SecretKeySpec(key, Algorithm.AES.getAlgorithm());
            this.cipher = Cipher.getInstance(Algorithm.AES.getAlgorithm());
            cipher.init(Cipher.DECRYPT_MODE, skeySpec);
        }
    }
}