com.drisoftie.cwdroid.util.CredentialUtils.java Source code

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Here is the source code for com.drisoftie.cwdroid.util.CredentialUtils.java

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/*
 * Copyright [2015] [Alexander Dridiger - drisoftie@gmail.com]
 *
 *      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 com.drisoftie.cwdroid.util;

import android.util.Base64;

import org.apache.commons.lang3.CharEncoding;

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

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

/**
 * @author Alexander Dridiger
 */
public class CredentialUtils {

    private static final String MD5 = "MD5";
    private static final String AES = "AES";

    private static Cipher getDefaultCipher() {
        Cipher cipher = null;
        try {
            cipher = Cipher.getInstance(AES);
        } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
            e.printStackTrace();
        }
        return cipher;
    }

    private static SecretKey generateKey() throws NoSuchAlgorithmException {
        // Generate a 256-bit key
        final int outputKeyLength = 256;

        SecureRandom secureRandom = new SecureRandom();
        // Do *not* seed secureRandom! Automatically seeded from system entropy.
        KeyGenerator keyGenerator = KeyGenerator.getInstance(AES);
        keyGenerator.init(outputKeyLength, secureRandom);
        return keyGenerator.generateKey();
    }

    public static byte[] generateKeyBytes() {
        byte[] keyBytes = null;
        try {
            keyBytes = generateKey().getEncoded();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return keyBytes;
    }

    public static String obfuscateToBase64(byte[] key, String pure) {
        String result = null;
        try {
            byte[] encrypted = encrypt(key, pure.getBytes());
            result = Base64.encodeToString(encrypted, Base64.DEFAULT);
        } catch (NoSuchPaddingException | NoSuchAlgorithmException | InvalidKeyException | BadPaddingException
                | IllegalBlockSizeException e) {
            e.printStackTrace();
        }
        return result;
    }

    public static String deobfuscateFromBase64(byte[] key, String basePassword) {
        String result = null;
        try {
            byte[] cleared = Base64.decode(basePassword, Base64.DEFAULT);
            byte[] decrypted = decrypt(key, cleared);
            result = new String(decrypted, CharEncoding.UTF_8);
        } catch (NoSuchPaddingException | NoSuchAlgorithmException | InvalidKeyException | BadPaddingException
                | IllegalBlockSizeException | UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return result;
    }

    private static byte[] encrypt(byte[] key, byte[] clear) throws NoSuchPaddingException, NoSuchAlgorithmException,
            InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        SecretKeySpec skeySpec = new SecretKeySpec(key, AES);
        Cipher cipher = getDefaultCipher();
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        return cipher.doFinal(clear);
    }

    private static byte[] decrypt(byte[] key, byte[] encrypted) throws NoSuchPaddingException,
            NoSuchAlgorithmException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        SecretKeySpec skeySpec = new SecretKeySpec(key, AES);
        Cipher cipher = getDefaultCipher();
        cipher.init(Cipher.DECRYPT_MODE, skeySpec);
        return cipher.doFinal(encrypted);
    }

    public static String md5(final String s) {
        try {
            // Create MD5 Hash
            MessageDigest digest = java.security.MessageDigest.getInstance(MD5);
            digest.update(s.getBytes());
            byte messageDigest[] = digest.digest();

            // Create Hex String
            StringBuilder hexString = new StringBuilder();
            for (byte aMessageDigest : messageDigest) {
                String h = Integer.toHexString(0xFF & aMessageDigest);
                while (h.length() < 2) {
                    h = "0" + h;
                }
                hexString.append(h);
            }
            return hexString.toString();

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return "";
    }
}