c# - .NET 中字符串的简单混淆？

Question

我需要通过互联网发送大约 30 个字符的字符串，这可能最终会成为另一家公司数据库中的 ID。

虽然字符串本身不会被识别，但我仍然希望它不会以任何方式被识别。

在 .NET 中混淆这样一个字符串的最简单方法是什么，以便在必要时可以轻松地反转它？

Answer 1

经典的东西（带有现代风格）怎么样。

public static string Caesar(this string source, Int16 shift)
{
    var maxChar = Convert.ToInt32(char.MaxValue);
    var minChar = Convert.ToInt32(char.MinValue);

    var buffer = source.ToCharArray();

    for (var i = 0; i < buffer.Length; i++)
    {
        var shifted = Convert.ToInt32(buffer[i]) + shift;

        if (shifted > maxChar)
        {
            shifted -= maxChar;
        }
        else if (shifted < minChar)
        {
            shifted += maxChar;
        }

        buffer[i] = Convert.ToChar(shifted);
    }

    return new string(buffer);
}

显然你会这样使用

var plain = "Wibble";
var caesered = plain.Caesar(42);
var newPlain = caesered.Caesar(-42);

它很快，您的密钥只是一个Int16，它会阻止不经意的观察者复制粘贴该值，但它并不安全。

Answer 2

怎么样：

    Convert.ToBase64String(Encoding.UTF8.GetBytes(myString));

及其相反：

    Encoding.UTF8.GetString(Convert.FromBase64String(myObfuscatedString));

只要您不介意增加字符串的长度

Answer 3

Try encrypting it with for example AES, if you know the encrypt key on the other machine you can easily decrypt it there

http://msdn.microsoft.com/en-us/library/system.security.cryptography.aes(v=vs.100).aspx

There are many code samples around. For example i found this post by a quick search, even though it's only 128 bit i think it should do the trick

Using AES encryption in C#

Answer 4

我受到@Jodrell 的回答的启发，这是我的替代版本。唯一真正的区别是我使用模运算符而不是 if-then-else 构造。

如果你和我一样，以前从未听说过凯撒密码，这里有一个链接：

https://en.wikipedia.org/wiki/Caesar_cipher

   public static partial class MString
   {
      ...

      /// <summary>
      /// Method to perform a very simple (and classical) encryption for a string. This is NOT at 
      /// all secure, it is only intended to make the string value non-obvious at a first glance.
      ///
      /// The shiftOrUnshift argument is an arbitrary "key value", and must be a non-zero integer 
      /// between -65535 and 65535 (inclusive). To decrypt the encrypted string you use the negative 
      /// value. For example, if you encrypt with -42, then you decrypt with +42, or vice-versa.
      ///
      /// This is inspired by, and largely based on, this:
      /// https://stackoverflow.com/a/13026595/253938
      /// </summary>
      /// <param name="inputString">string to be encrypted or decrypted, must not be null</param>
      /// <param name="shiftOrUnshift">see above</param>
      /// <returns>encrypted or decrypted string</returns>
      public static string CaesarCipher(string inputString, int shiftOrUnshift)
      {
         // Check C# is still C#
         Debug.Assert(char.MinValue == 0 && char.MaxValue == UInt16.MaxValue);

         const int C64K = UInt16.MaxValue + 1;

         // Check the arguments
         if (inputString == null)
            throw new ArgumentException("Must not be null.", "inputString");
         if (shiftOrUnshift == 0)
            throw new ArgumentException("Must not be zero.", "shiftOrUnshift");
         if (shiftOrUnshift <= -C64K || shiftOrUnshift >= C64K)
            throw new ArgumentException("Out of range.", "shiftOrUnshift");

         // Perform the Caesar cipher shifting, using modulo operator to provide wrap-around
         char[] charArray = new char[inputString.Length];
         for (int i = 0; i < inputString.Length; i++)
         {
            charArray[i] = 
                  Convert.ToChar((Convert.ToInt32(inputString[i]) + shiftOrUnshift + C64K) % C64K);
         }

         // Return the result as a new string
         return new string(charArray);
      }

      ...
   }

还有一些测试代码：

     // Test CaesarCipher() method
     const string CHelloWorld = "Hello world!";
     const int CCaesarCipherKey = 42;
     string caesarCiphered = MString.CaesarCipher(CHelloWorld, CCaesarCipherKey);
     if (MString.CaesarCipher(caesarCiphered, -CCaesarCipherKey) != CHelloWorld)
        throw new Exception("Oh no!");