// 定义密钥
import 'dart:convert';

List skey = [8, 1, 2, 5, 4];

// 单个字符异或运算
String makecodeChar(String c, int key, int key2) {
  int charCode = c.codeUnitAt(0);
  charCode = (((charCode + key) ^ key2) ^ key) + 1;
  return String.fromCharCode(charCode);
}

// 单个字符解密
String cutcodeChar(String c, int key, int key2) {
  int charCode = c.codeUnitAt(0);
  int decryptedCharCode = (((charCode - 1) ^ key) ^ key2) - key;
  return String.fromCharCode(decryptedCharCode);
}

// 加密
String makecode(String pstr, List pkey) {
  String pp = pstr;
  for (int i = 0; i < pp.length; i++) {
    pp = pp.replaceRange(i, i + 1, makecodeChar(pp[i], pkey[i % 5], pkey[(i + 18) % 5]));
  }
  return pp;
}

// 解密
String cutecode(List<int> pstr) {
  int len = pstr.length;
  for (int i = 0; i < len; i++) {
    pstr[i] = cutcodeChar(String.fromCharCode(pstr[i])
        , skey[i % 5], skey[(i + 18) % 5]).codeUnitAt(0);
  }
  return String.fromCharCodes(pstr);
}