com.lingdonge.crypto.encrypt.AuthCode Maven / Gradle / Ivy
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package com.lingdonge.crypto.encrypt;
import com.lingdonge.core.encode.Base64Util;
import java.util.Random;
/**
* Java实现Discuz的加密算法
*/
public class AuthCode {
/**
*
*/
public enum DiscuzAuthcodeMode {
Encode, Decode
}
// private static MD5 md5 = new MD5();
// private static BASE64 base64 = new BASE64();
/**
* 从字符串的指定位置截取指定长度的子字符串
*
* @param str 原字符串
* @param startIndex 子字符串的起始位置
* @param length 子字符串的长度
* @return 子字符串
*/
public static String CutString(String str, int startIndex, int length) {
if (startIndex >= 0) {
if (length < 0) {
length = length * -1;
if (startIndex - length < 0) {
length = startIndex;
startIndex = 0;
} else {
startIndex = startIndex - length;
}
}
if (startIndex > str.length()) {
return "";
}
} else {
if (length < 0) {
return "";
} else {
if (length + startIndex > 0) {
length = length + startIndex;
startIndex = 0;
} else {
return "";
}
}
}
if (str.length() - startIndex < length) {
length = str.length() - startIndex;
}
return str.substring(startIndex, startIndex + length);
}
/**
* 从字符串的指定位置开始截取到字符串结尾的了符串
*
* @param str 原字符串
* @param startIndex 子字符串的起始位置
* @return 子字符串
*/
public static String CutString(String str, int startIndex) {
return CutString(str, startIndex, str.length());
}
/**
* 用于 RC4 处理密码
*
* @param pass 密码字串
* @param kLen 密钥长度，一般为 256
* @return
*/
static private byte[] GetKey(byte[] pass, int kLen) {
byte[] mBox = new byte[kLen];
for (int i = 0; i < kLen; i++) {
mBox[i] = (byte) i;
}
int j = 0;
for (int i = 0; i < kLen; i++) {
j = (j + (int) ((mBox[i] + 256) % 256) + pass[i % pass.length])
% kLen;
byte temp = mBox[i];
mBox[i] = mBox[j];
mBox[j] = temp;
}
return mBox;
}
/**
* 生成随机字符
*
* @param lens 随机字符长度
* @return 随机字符
*/
public static String RandomString(int lens) {
char[] CharArray = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k',
'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
int clens = CharArray.length;
String sCode = "";
Random random = new Random();
for (int i = 0; i < lens; i++) {
sCode += CharArray[Math.abs(random.nextInt(clens))];
}
return sCode;
}
/**
* 使用 Discuz authcode 方法对字符串加密
*
* @param source 原始字符串
* @param key 密钥
* @param expiry 加密字串有效时间，单位是秒
* @return 加密结果
*/
public static String authcodeEncode(String source, String key, int expiry) {
return authcode(source, key, DiscuzAuthcodeMode.Encode, expiry);
}
/**
* 使用 Discuz authcode 方法对字符串加密
*
* @param source 原始字符串
* @param key 密钥
* @return 加密结果
*/
public static String authcodeEncode(String source, String key) {
return authcode(source, key, DiscuzAuthcodeMode.Encode, 0);
}
/**
* 使用 Discuz authcode 方法对字符串解密
*
* @param source 原始字符串
* @param key 密钥
* @return 解密结果
*/
public static String authcodeDecode(String source, String key) {
return authcode(source, key, DiscuzAuthcodeMode.Decode, 0);
}
/**
* 使用 变形的 rc4 编码方法对字符串进行加密或者解密
*
* @param source 原始字符串
* @param key 密钥
* @param operation 操作类型，加密还是解密
* @param expiry 加密字串过期时间
* @return 加密或者解密后的字符串
*/
private static String authcode(String source, String key, DiscuzAuthcodeMode operation, int expiry) {
try {
if (source == null || key == null) {
return "";
}
int ckey_length = 4;
String keya, keyb, keyc, cryptkey, result;
key = Md5Util.getMd5(key);
keya = Md5Util.getMd5(CutString(key, 0, 16));
keyb = Md5Util.getMd5(CutString(key, 16, 16));
keyc = ckey_length > 0 ? (operation == DiscuzAuthcodeMode.Decode ? CutString(
source, 0, ckey_length) : RandomString(ckey_length))
: "";
cryptkey = keya + Md5Util.getMd5(keya + keyc);
if (operation == DiscuzAuthcodeMode.Decode) {
byte[] temp;
temp = Base64Util.decode(CutString(source, ckey_length));
result = new String(RC4(temp, cryptkey));
if (CutString(result, 10, 16).equals(
CutString(Md5Util.getMd5(CutString(result, 26) + keyb), 0, 16))) {
return CutString(result, 26);
} else {
temp = Base64Util.decode(CutString(source + "=", ckey_length));
result = new String(RC4(temp, cryptkey));
if (CutString(result, 10, 16)
.equals(CutString(
Md5Util.getMd5(CutString(result, 26) + keyb), 0, 16))) {
return CutString(result, 26);
} else {
temp = Base64Util.decode(CutString(source + "==", ckey_length));
result = new String(RC4(temp, cryptkey));
if (CutString(result, 10, 16).equals(
CutString(Md5Util.getMd5(CutString(result, 26) + keyb), 0,
16))) {
return CutString(result, 26);
} else {
return "2";
}
}
}
} else {
source = "0000000000" + CutString(Md5Util.getMd5(source + keyb), 0, 16) + source;
byte[] temp = RC4(source.getBytes("GBK"), cryptkey);
return keyc + Base64Util.encodeToStr(temp);
}
} catch (Exception e) {
return "";
}
}
/**
* RC4 原始算法
*
* @param input 原始字串数组
* @param pass 密钥
* @return 处理后的字串数组
*/
private static byte[] RC4(byte[] input, String pass) {
if (input == null || pass == null) {
return null;
}
byte[] output = new byte[input.length];
byte[] mBox = GetKey(pass.getBytes(), 256);
// 加密
int i = 0;
int j = 0;
for (int offset = 0; offset < input.length; offset++) {
i = (i + 1) % mBox.length;
j = (j + (int) ((mBox[i] + 256) % 256)) % mBox.length;
byte temp = mBox[i];
mBox[i] = mBox[j];
mBox[j] = temp;
byte a = input[offset];
// byte b = mBox[(mBox[i] + mBox[j] % mBox.Length) % mBox.Length];
// mBox[j] 一定比 mBox.Length 小，不需要在取模
byte b = mBox[(toInt(mBox[i]) + toInt(mBox[j])) % mBox.length];
output[offset] = (byte) ((int) a ^ (int) toInt(b));
}
return output;
}
public static int toInt(byte b) {
return (int) ((b + 256) % 256);
}
}