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由于游戏对数据包的传输内容很关注，如果写的不好很容易被破解。我这里采用的是json传输数据，所以要对数据进行加密解密，用来更方便的做操作。
基本加密顺序就是 JSON字符串->Base64字符串->DES加密
其中
Base64是一重加密
Base64里面我改进了算法，支持任意形式的字典表，所以这个地方是第二重加密
DES在Base64的基础上再次用秘钥加密。
有人问为什么还需要改Base64的字典表，其实原因就是DES的秘钥只能是8个字节，按照现在计算机的处理速度，24小时就破解了。
首先我们要有个处理Base64的处理类，这里我把网上一个公开的类库做了改进，做了一个混排编码格式
public class Base64 {
private static final char[] legalChars = "ghijk67stuJKLM89rvwxyzAlmnOUV+/abcdefPQRSTopqCDEFG012345BHINWXYZ"
.toCharArray();//字典内顺序任意更改，只要内容保证不缺就行
private static HashMap<Character,Integer> hashDecode=new HashMap<Character,Integer>();
/**
* 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();
}
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;
}
}
private static int decode(char c) {
if(hashDecode.size()==0)
{
for(int i =0;i<64;i++)
{ char ch = legalChars[i];
hashDecode.put(ch, i);
}
}
if(hashDecode.containsKey(c))
{
return hashDecode.get(c);
}
else if(c =='=')
return 0;
else
throw new RuntimeException("unexpected code: " + c);
}
}
然后是Des加密算法
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
public class DateSecret {
private static String keyCode="123456";//秘钥可以任意改，只要总长度是8个字节就行
private static byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };
public static String encryptDES(String encryptString)
throws Exception {
IvParameterSpec zeroIv = new IvParameterSpec(iv);
SecretKeySpec key = new SecretKeySpec(keyCode.getBytes(), "DES");
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);
byte[] encryptedData = cipher.doFinal(encryptString.getBytes("utf-8"));
return Base64.encode(encryptedData);
}
public static String decryptDES(String decryptString)
throws Exception {
byte[] byteMi = Base64.decode(decryptString);
IvParameterSpec zeroIv = new IvParameterSpec(iv);
SecretKeySpec key = new SecretKeySpec(keyCode.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 ,"utf-8");
}
/**将二进制转换成16进制
* @param buf
* @return String
*/
public static String parseByte2HexStr(byte buf[]) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < buf.length; i++) {
String hex = Integer.toHexString(buf[i] & 0xFF);
if (hex.length() == 1) {
hex = '0' + hex;
}
sb.append(hex.toUpperCase());
}
return sb.toString();
}
}
使用示例
String strDecode = DateSecret.decryptDES(str);//解密
String strOut = DateSecret.encryptDES(str);//加密
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