C#实现简易的加密、解密字符串工具类实例

本文实例讲述了c#实现简易的加密、解密字符串工具类。分享给大家供大家参考。具体如下：

这里的类cypherhelper是一个用于加密、解密字符串的工具类~~~，适合于方便地加密、解密长度较短的密码等字符串（c#里面已经有了库system.security.cryptography，对于比较长的字符串或流来说是一个更好的选择）

类cypherhelper代码：

class cypherhelper
{
 /// <summary>
 /// 加密字符串
 /// </summary>
 /// <param name="word">被加密字符串</param>
 /// <param name="key">密钥</param>
 /// <returns>加密后字符串</returns>
 public static string encrypt(string word, string key)
 {
  if (!system.text.regularexpressions.regex.ismatch(key, "^[a-za-z]*$"))
  {
   throw new exception("key 必须由字母组成");
  }
  key = key.tolower();
  //逐个字符加密字符串
  char[] s = word.tochararray();
  for (int i = 0; i < s.length; i++)
  {
   char a = word[i];
   char b = key[i % key.length];
   s[i] = encryptchar(a, b);
  }
  return new string(s);
 }
 /// <summary>
 /// 加密单个字符
 /// </summary>
 /// <param name="a">被加密字符</param>
 /// <param name="b">密钥</param>
 /// <returns>加密后字符</returns>
 private static char encryptchar(char a, char b)
 {
  int c = a + b - 'a';
  if (a >= '0' && a <= '9') //字符0-9的转换
  {
   while (c > '9') c -= 10;
  }
  else if (a >= 'a' && a <= 'z') //字符a-z的转换
  {
   while (c > 'z') c -= 26;
  }
  else if (a >= 'a' && a <= 'z') //字符a-z的转换
  {
   while (c > 'z') c -= 26;
  }
  else return a; //不再上面的范围内，不转换直接返回
  return (char)c; //返回转换后的字符
 }
 /// <summary>
 /// 解密字符串
 /// </summary>
 /// <param name="word">被解密字符串</param>
 /// <param name="key">密钥</param>
 /// <returns>解密后字符串</returns>
 public static string decrypt(string word, string key)
 {
  if (!system.text.regularexpressions.regex.ismatch(key, "^[a-za-z]*$"))
  {
   throw new exception("key 必须由字母组成");
  }
  key = key.tolower();
  //逐个字符解密字符串
  char[] s = word.tochararray();
  for (int i = 0; i < s.length; i++)
  {
   char a = word[i];
   char b = key[i % key.length];
   s[i] = decryptchar(a, b);
  }
  return new string(s);
 }
 /// <summary>
 /// 解密单个字符
 /// </summary>
 /// <param name="a">被解密字符</param>
 /// <param name="b">密钥</param>
 /// <returns>解密后字符</returns>
 private static char decryptchar(char a, char b)
 {
  int c = a - b + 'a';
  if (a >= '0' && a <= '9') //字符0-9的转换
  {
   while (c < '0') c += 10;
  }
  else if (a >= 'a' && a <= 'z') //字符a-z的转换
  {
   while (c < 'a') c += 26;
  }
  else if (a >= 'a' && a <= 'z') //字符a-z的转换
  {
   while (c < 'a') c += 26;
  }
  else return a; //不再上面的范围内，不转换直接返回
  return (char)c; //返回转换后的字符
 }
}

main函数调用示例

class program
{
 static void main(string[] args)
 {
  //1.加密
  string a = cypherhelper.encrypt("tsybiuslee1234", "galatea");
  console.writeline("加密：tsybiuslee1234 → " + a);
  //2.解密
  string b = cypherhelper.decrypt(a, "galatea");
  console.writeline("解密：" + a + " → " + b);
  console.readline();
 }
}

运行结果

希望本文所述对大家的c#程序设计有所帮助。