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22-09-2019 - |
题
我写在C#
这个代码进行加密用密钥的字符串:
private static int Bin2Dec(string num)
{
int _num = 0;
for (int i = 0; i < num.Length; i++)
_num += (int)Math.Pow(2, num.Length - i - 1) * int.Parse(num[i].ToString());
return _num;
}
private static string Dec2Bin(int num)
{
if (num < 2) return num.ToString();
return Dec2Bin(num / 2) + (num % 2).ToString();
}
public static string StrXor(string str, string key)
{
string _str = "";
string _key = "";
string _xorStr = "";
string _temp = "";
for (int i = 0; i < str.Length; i++)
{
_temp = Dec2Bin(str[i]);
for (int j = 0; j < 8 - _temp.Length + 1; j++)
_temp = '0' + _temp;
_str += _temp;
}
for (int i = 0; i < key.Length; i++)
{
_temp = Dec2Bin(key[i]);
for (int j = 0; j < 8 - _temp.Length + 1; j++)
_temp = '0' + _temp;
_key += _temp;
}
while (_key.Length < _str.Length) _key += _key;
if (_key.Length > _str.Length) _key = _key.Substring(0, _str.Length);
for (int i = 0; i < _str.Length; i++)
if (_str[i] == _key[i]) { _xorStr += '0'; } else { _xorStr += '1'; }
_str = "";
for (int i = 0; i < _xorStr.Length; i += 8)
{
char _chr = (char)0;
_chr = (char)Bin2Dec(_xorStr.Substring(i, 8)); //ERROR : (Index and length must refer to a location within the string. Parameter name: length)
_str += _chr;
}
return _str;
}
问题是,当我想解密使用此代码encryted文本,我总是得到错误:
string enc_text = ENCRYPT.XORENC("abc","a"); // enc_text = " ♥☻"
string dec_text = ENCRYPT.XORENC(enc_text,"a"); // ArgumentOutOfRangeException
任何线索?
解决方案
如果你有字符,char
,可以将其转换为整数,一个int
。
然后你可以使用^
运营商对其执行XOR。您似乎没有被使用运营商的那一刻,这可能是你的问题的根源。
string EncryptOrDecrypt(string text, string key)
{
var result = new StringBuilder();
for (int c = 0; c < text.Length; c++)
result.Append((char)((uint)text[c] ^ (uint)key[c % key.Length]));
return result.ToString();
}
这之类的话。下面是与评论较长的版本,那么在步骤同样的事情,以使其更易于学习和借鉴:
string EncryptOrDecrypt(string text, string key)
{
var result = new StringBuilder();
for (int c = 0; c < text.Length; c++)
{
// take next character from string
char character = text[c];
// cast to a uint
uint charCode = (uint)character;
// figure out which character to take from the key
int keyPosition = c % key.Length; // use modulo to "wrap round"
// take the key character
char keyChar = key[keyPosition];
// cast it to a uint also
uint keyCode = (uint)keyChar;
// perform XOR on the two character codes
uint combinedCode = charCode ^ keyCode;
// cast back to a char
char combinedChar = (char)combinedCode;
// add to the result
result.Append(combineChar);
}
return result.ToString();
}
短的版本是相同的,但移除了中间变量,直接代入表达式他们已经习惯的位置。
其他提示
public static byte[] EncryptOrDecrypt(byte[] text, byte[] key)
{
byte[] xor = new byte[text.Length];
for (int i = 0; i < text.Length; i++)
{
xor[i] = (byte)(text[i] ^ key[i % key.Length]);
}
return xor;
}
static void Main(string[] args){
string input;
byte[] inputBytes;
string inputKey;
byte[] key;
do
{
input = System.Console.ReadLine();
inputBytes = Encoding.Unicode.GetBytes(input);
inputKey = System.Console.ReadLine();
key = Encoding.Unicode.GetBytes(inputKey);
//byte[] key = { 0, 0 }; if key is 0, encryption will not happen
byte[] encryptedBytes = EncryptOrDecrypt(inputBytes, key);
string encryptedStr = Encoding.Unicode.GetString(encryptedBytes);
byte[] decryptedBytes = EncryptOrDecrypt(encryptedBytes, key);
string decryptedStr = Encoding.Unicode.GetString(decryptedBytes);
System.Console.WriteLine("Encrypted string:");
System.Console.WriteLine(encryptedStr);
System.Console.WriteLine("Decrypted string:");
System.Console.WriteLine(decryptedStr);
} while (input != "-1" && inputKey != "-1");
//test:
//pavle
//23
//Encrypted string:
//BRD_W
//Decrypted string:
//pavle
}
下面是一些简单的代码进行加密和解密
class CEncryption
{
public static string Encrypt(string strIn, string strKey)
{
string sbOut = String.Empty;
for (int i = 0; i < strIn.Length; i++)
{
sbOut += String.Format("{0:00}", strIn[i] ^ strKey[i % strKey.Length]);
}
return sbOut;
}
public static string Decrypt(string strIn, string strKey)
{
string sbOut = String.Empty;
for (int i = 0; i < strIn.Length; i += 2)
{
byte code = Convert.ToByte(strIn.Substring(i, 2));
sbOut += (char)(code ^ strKey[(i/2) % strKey.Length]);
}
return sbOut;
}
}
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