C#實現簡易的加密、解密字符串工具類實例

2020-01-24 01:31:40

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本文實例講述了C#實現簡易的加密、解密字符串工具類。分享給大家供大家參考。具體如下：

這里的類CypherHelper是一個用于加密、解密字符串的工具類~~~，適合于方便地加密、解密長度較短的密碼等字符串（C#里面已經有了庫System.Security.Cryptography，對于比較長的字符串或流來說是一個更好的選擇）

類CypherHelper代碼：

class CypherHelper{ /// <summary> /// 加密字符串 /// </summary> /// <param name="word">被加密字符串</param> /// <param name="key">密鑰</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]*$"))  {   throw new Exception("key 必須由字母組成");  }  key = key.ToLower();  //逐個字符加密字符串  char[] s = word.ToCharArray();  for (int i = 0; i < s.Length; i++)  {   char a = word[i];   char b = key[i % key.Length];   s[i] = EncryptChar(a, b);  }  return new string(s); } /// <summary> /// 加密單個字符 /// </summary> /// <param name="a">被加密字符</param> /// <param name="b">密鑰</param> /// <returns>加密后字符</returns> private static char EncryptChar(char a, char b) {  int c = a + b - 'a';  if (a >= '0' && a <= '9') //字符0-9的轉換  {   while (c > '9') c -= 10;  }  else if (a >= 'a' && a <= 'z') //字符a-z的轉換  {   while (c > 'z') c -= 26;  }  else if (a >= 'A' && a <= 'Z') //字符A-Z的轉換  {   while (c > 'Z') c -= 26;  }  else return a; //不再上面的范圍內，不轉換直接返回  return (char)c; //返回轉換后的字符 } /// <summary> /// 解密字符串 /// </summary> /// <param name="word">被解密字符串</param> /// <param name="key">密鑰</param> /// <returns>解密后字符串</returns> public static string Decrypt(string word, string key) {  if (!System.Text.RegularExpressions.Regex.IsMatch(key, "^[a-zA-Z]*$"))  {   throw new Exception("key 必須由字母組成");  }  key = key.ToLower();  //逐個字符解密字符串  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> /// 解密單個字符 /// </summary> /// <param name="a">被解密字符</param> /// <param name="b">密鑰</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的轉換  {   while (c < '0') c += 10;  }  else if (a >= 'a' && a <= 'z') //字符a-z的轉換  {   while (c < 'a') c += 26;  }  else if (a >= 'A' && a <= 'Z') //字符A-Z的轉換  {   while (c < 'A') c += 26;  }  else return a; //不再上面的范圍內，不轉換直接返回  return (char)c; //返回轉換后的字符 }}

Main函數調用示例

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(); }}

運行結果