初步加密思想

   作为我们这一行，最重要的就是保护数据。。。所以，在接受服务端的数据或者传送过去的时候，我们都要保护好·自己的数据，这样起步，谁也不伤害谁！嘿嘿。。。

   然后自己这里呢，有一个的demo，这样是吧加密提取出来的，然后想要用，随时可以用就ok！

     这是base64：

package com.android.utills;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class Base64 {

    private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
            .toCharArray();

    /**
     * data[]进行编码
     * 
     * @param data
     * @return
     */
    public static String encode(byte[] data) {
        int start = 0;
        int len = data.length;
        StringBuffer buf = new StringBuffer(data.length * 3 / 2);

        int end = len - 3;
        int i = start;
        int n = 0;

        while (i <= end) {
            int d = ((((int) data[i]) & 0x0ff) << 16)
                    | ((((int) data[i + 1]) & 0x0ff) << 8)
                    | (((int) data[i + 2]) & 0x0ff);

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append(legalChars[(d >> 6) & 63]);
            buf.append(legalChars[d & 63]);

            i += 3;

            if (n++ >= 14) {
                n = 0;
                buf.append(" ");
            }
        }

        if (i == start + len - 2) {
            int d = ((((int) data[i]) & 0x0ff) << 16)
                    | ((((int) data[i + 1]) & 255) << 8);

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append(legalChars[(d >> 6) & 63]);
            buf.append("=");
        } else if (i == start + len - 1) {
            int d = (((int) data[i]) & 0x0ff) << 16;

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append("==");
        }

        return buf.toString();
    }

    private static int decode(char c) {
        if (c >= 'A' && c <= 'Z')
            return ((int) c) - 65;
        else if (c >= 'a' && c <= 'z')
            return ((int) c) - 97 + 26;
        else if (c >= '0' && c <= '9')
            return ((int) c) - 48 + 26 + 26;
        else
            switch (c) {
            case '+':
                return 62;
            case '/':
                return 63;
            case '=':
                return 0;
            default:
                throw new RuntimeException("unexpected code: " + c);
            }
    }

    /**
     * Decodes the given Base64 encoded String to a new byte array. The byte
     * array holding the decoded data is returned.
     */

    public static byte[] decode(String s) {

        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try {
            decode(s, bos);
        } catch (IOException e) {
            throw new RuntimeException();
        }
        byte[] decodedBytes = bos.toByteArray();
        try {
            bos.close();
            bos = null;
        } catch (IOException ex) {
            System.err.println("Error while decoding BASE64: " + ex.toString());
        }
        return decodedBytes;
    }

    private static void decode(String s, OutputStream os) throws IOException {
        int i = 0;

        int len = s.length();

        while (true) {
            while (i < len && s.charAt(i) <= ' ')
                i++;

            if (i == len)
                break;

            int tri = (decode(s.charAt(i)) << 18)
                    + (decode(s.charAt(i + 1)) << 12)
                    + (decode(s.charAt(i + 2)) << 6)
                    + (decode(s.charAt(i + 3)));

            os.write((tri >> 16) & 255);
            if (s.charAt(i + 2) == '=')
                break;
            os.write((tri >> 8) & 255);
            if (s.charAt(i + 3) == '=')
                break;
            os.write(tri & 255);

            i += 4;
        }
    }

}

这是DES：

package com.android.utills;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * DES加密工具类
 */
public class DesUtil {

    private static byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };

    public static String encryptDES(String encryptString, String encryptKey)
            throws Exception {
        // IvParameterSpec zeroIv = new IvParameterSpec(new byte[8]);
        IvParameterSpec zeroIv = new IvParameterSpec(iv);
        SecretKeySpec key = new SecretKeySpec(encryptKey.getBytes(), "DES");
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);
        byte[] encryptedData = cipher.doFinal(encryptString.getBytes());

        return Base64.encode(encryptedData);
    }

    public static String decryptDES(String decryptString, String decryptKey)
            throws Exception {
        byte[] byteMi = new Base64().decode(decryptString);
        IvParameterSpec zeroIv = new IvParameterSpec(iv);
        // IvParameterSpec zeroIv = new IvParameterSpec(new byte[8]);
        SecretKeySpec key = new SecretKeySpec(decryptKey.getBytes(), "DES");
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, key, zeroIv);
        byte decryptedData[] = cipher.doFinal(byteMi);

        return new String(decryptedData);

    }

    /*
     * private static final String ENCRYPT_TYPE = "DES"; private static String
     * defaultKey = "";// 字符串默认键值 private Cipher encryptCipher = null;// 加密工具
     * private Cipher decryptCipher = null;// 解密工具
     * 
     * public DesUtil() throws Exception { this(defaultKey); }
     *//**
     * 指定密钥构造方法
     * 
     * @param strKey
     *            指定的密钥
     * @throws Exception
     */
    /*
     * public DesUtil(String strKey) throws Exception { Security.addProvider(new
     * com.sun.crypto.provider.SunJCE()); Key key = getKey(strKey.getBytes());
     * encryptCipher = Cipher.getInstance(ENCRYPT_TYPE);
     * encryptCipher.init(Cipher.ENCRYPT_MODE, key); decryptCipher =
     * Cipher.getInstance(ENCRYPT_TYPE); decryptCipher.init(Cipher.DECRYPT_MODE,
     * key); }
     *//**
     * 加密字节数组
     * 
     * @param arr
     *            需加密的字节数组
     * @return 加密后的字节数组
     * @throws Exception
     */
    /*
     * private byte[] encryptStr(byte[] arr) throws Exception { return
     * encryptCipher.doFinal(arr); }
     *//**
     * 加密字符串
     * 
     * @param strIn
     *            需加密的字符串
     * @return 加密后的字符串
     * @throws Exception
     */
    /*
     * public String encrypt(String strIn) throws Exception { return
     * StrConvertUtil.byteArrToHexStr(encryptStr(strIn.getBytes())); }
     *//**
     * 解密字节数组
     * 
     * @param arr
     *            需解密的字节数组
     * @return 解密后的字节数组
     * @throws Exception
     */
    /*
     * private byte[] decryptStr(byte[] arr) throws Exception { return
     * decryptCipher.doFinal(arr); }
     *//**
     * 解密字符串
     * 
     * @param strIn
     *            需解密的字符串
     * @return 解密后的字符串
     * @throws Exception
     */
    /*
     * public String decrypt(String strIn) throws Exception { return new
     * String(decryptStr(StrConvertUtil.hexStrToByteArr(strIn))); }
     *//**
     * 从指定字符串生成密钥，密钥所需的字节数组长度为8位。不足8位时后面补0，超出8位只取前8位
     * 
     * @param arrBTmp
     *            构成该字符串的字节数组
     * @return 生成的密钥
     */
    /*
     * private Key getKey(byte[] arrBTmp) { byte[] arrB = new byte[8];//
     * 创建一个空的8位字节数组（默认值为0） // 将原始字节数组转换为8位 for (int i = 0; i < arrBTmp.length &&
     * i < arrB.length; i++) { arrB[i] = arrBTmp[i]; } Key key = new
     * javax.crypto.spec.SecretKeySpec(arrB, ENCRYPT_TYPE);// 生成密钥 return key; }
     */
}

这是MD5：

package com.android.utills;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * MD5加密工具类
 * 
 */
public class Md5Util {

    /**
     * 根据输入的字符串生成固定的32位MD5码
     * 
     * @param str
     *            输入的字符串
     * @return MD5码
     */
    public final static String getMd5(String str) {
        MessageDigest mdInst = null;
        try {
            mdInst = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        mdInst.update(str.getBytes());// 使用指定的字节更新摘要
        byte[] md = mdInst.digest();// 获得密文
        return StrConvertUtil.byteArrToHexStr(md);
    }
}

这是转换：

package com.android.utills;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * MD5加密工具类
 * 
 */
public class Md5Util {

    /**
     * 根据输入的字符串生成固定的32位MD5码
     * 
     * @param str
     *            输入的字符串
     * @return MD5码
     */
    public final static String getMd5(String str) {
        MessageDigest mdInst = null;
        try {
            mdInst = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        mdInst.update(str.getBytes());// 使用指定的字节更新摘要
        byte[] md = mdInst.digest();// 获得密文
        return StrConvertUtil.byteArrToHexStr(md);
    }
}

okay、。。

当然，这里还有提供详细加密的路径链接：

http://apprentice.blog.51cto.com/2214645/1381824

http://hi.baidu.com/cuihenrychl/item/751966f0c31e310acf9f32e4?qq-pf-to=pcqq.c2c