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
希望本文所述對大家的C#程序設計有所幫助。
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