Android实现DES和3DES算法(2)

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();
    }
}

调用

//DES
 //DES加密
 byte[] en = DESUtils.enCode(hexStringToBytes("3132333435363738"), "A1A2A3A4A5A6A7A8");
 //DES解密 
 try {
  byte[] dn = DESUtils.deCode(hexStringToBytes("B1C3D2A87DBDB68FA73FBBBCD6F083AC"), "A1A2A3A4A5A6A7A8");
   
 } catch (Exception e) {
  e.printStackTrace();
 }
 
//3DES
 //3DES加密
 String key =  "A1A2A3A4A5A6A7A8" //K1密钥
   +"B1B2B3B4B5B6B7B8" //K2密钥
   +"A1A2A3A4A5A6A7A8"; //K3密钥
 byte[] result = DES3Utils.encryptMode(hexStringToBytes(key), hexStringToBytes("3132333435363738"));

//3DES解密
 byte[] dnresult = DES3Utils.decryptMode(hexStringToBytes(key), hexStringToBytes("B0920ED6520EAF752E22A1F49B243353"));

//***************************************************************************************
 //实现String到byte的转换
 public static byte[] hexStringToBytes(String string) {
        String hexString = string.replaceAll(" ", "").toUpperCase();

        if (hexString.length() <= 0)
            return null;

        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;
    } 

DES的明文是3132333435363738，密钥是A1A2A3A4A5A6A7A8，加密后得到B1C3D2A87DBDB68FA73FBBBCD6F083AC，这里面前面16位是明文加密而来的，后面的A73FBBBCD6F083AC是由0808080808080808加密而来的。这8个08是算法自动填充上去的。3DES同样会填充8个08上去再加密。B0920ED6520EAF752E22A1F49B243353后面的2E22A1F49B243353是由填充的0808080808080808加密而来。