导言:
由于数据的安全性,所以需要进行数据加密和解密处理,当然有很多算法,但其中MD5不可逆,3DES(DESede)是DES的升级版,所以本文只是笔记

步骤:
1:MD5加密,很简单,直接将需要加密的字符串传入即可.

public static String MD5Tool(String str) {
        if (TextUtils.isEmpty(str)) {
            return "";
        }
        try {
            MessageDigest mDigest = MessageDigest.getInstance("MD5");
            byte[] bytes = mDigest.digest(str.getBytes());
            String result = "";
            for (byte bt : bytes) {
                String temp = Integer.toHexString(bt & 0xff);
                if (temp.length() == 1) {
                    temp = "0" + temp;
                }
                result += temp;
            }
            return result;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "";
    }

2:3DES重要加密解密类

public class DES3Util {
    private static final String TYPE = "DESede";

    //加密
    public static byte[] encryptMode(byte[] keybyte, byte[] src) {
        try {
            SecretKey deskey = new SecretKeySpec(keybyte, TYPE);
            Cipher c1 = Cipher.getInstance(TYPE);
            c1.init(Cipher.ENCRYPT_MODE, deskey);
            return c1.doFinal(src);
        } catch (java.security.NoSuchAlgorithmException e1) {
            e1.printStackTrace();
        } catch (javax.crypto.NoSuchPaddingException e2) {
            e2.printStackTrace();
        } catch (java.lang.Exception e3) {
            e3.printStackTrace();
        }
        return null;
    }

    //解密
    public static byte[] decryptMode(byte[] keybyte, byte[] src) {
        try {
            SecretKey deskey = new SecretKeySpec(keybyte, TYPE);
            Cipher c1 = Cipher.getInstance(TYPE);
            c1.init(Cipher.DECRYPT_MODE, deskey);
            return c1.doFinal(src);
        } catch (java.security.NoSuchAlgorithmException e1) {
            e1.printStackTrace();
        } catch (javax.crypto.NoSuchPaddingException e2) {
            e2.printStackTrace();
        } catch (java.lang.Exception e3) {
            e3.printStackTrace();
        }
        return null;
    }

    //byte->hexString
    public static String byte2hex(byte[] b) {
        String hs = "";
        String stmp = "";
        for (int n = 0; n < b.length; n++) {
            stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
            if (stmp.length() == 1) hs = hs + "0" + stmp;
            else hs = hs + stmp;
            if (n < b.length - 1) hs = hs + "";
        }
        return hs.toUpperCase();
    }

    //hexString->byte
    public static byte[] hexStringToBytes(String hexString) {
        if (hexString == null || hexString.equals("")) {
            return null;
        }
        hexString = hexString.toUpperCase();
        int length = hexString.length() / 2;
        char[] hexChars = hexString.toCharArray();
        byte[] d = new byte[length];
        for (int i = 0; i < length; i++) {
            int pos = i * 2;
            d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
        }
        return d;
    }

    private static byte charToByte(char c) {
        return (byte) "0123456789ABCDEF".indexOf(c);
    }
}

3:使用3DES加密解密样例

//三个不同秘钥
String key = "B1B2B3B4B5B6B7B8" + "A1A2A3A4A5A6A7A8" + "A1B2A3A4A5A6A7F8";
Sting src="[email protected]";
//加密
String encryResult = byte2hex(encryptMode(hexStringToBytes(key), src.getBytes("UTF-8")));
//解密
String decryptResult = new String(decryptMode(hexStringToBytes(key), hexStringToBytes(encryResult)), "UTF-8");

结束