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。