在C#中使用对称加密技术可以通过使用内置的加密算法类来实现。以下是一种在C#中使用对称加密技术的示例：
using System;using System.Security.Cryptography;using System.Text;class Program{ static void Main() { string originalText = "Hello World!"; string key = "mysecretkey"; // 16 bytes key for AES encryption byte[] encryptedData = Encrypt(originalText, key); string decryptedText = Decrypt(encryptedData, key); Console.WriteLine($"Original Text: {originalText}"); Console.WriteLine($"Encrypted Data: {Convert.ToBase64String(encryptedData)}"); Console.WriteLine($"Decrypted Text: {decryptedText}"); } static byte[] Encrypt(string text, string key) { using (Aes aes = Aes.Create()) { aes.Key = Encoding.UTF8.GetBytes(key); aes.IV = new byte[16]; // 16 bytes Initialization Vector for AES encryption using (ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV)) { byte[] data = Encoding.UTF8.GetBytes(text); using (MemoryStream ms = new MemoryStream()) { using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write)) { cs.Write(data, 0, data.Length); cs.FlushFinalBlock(); return ms.ToArray(); } } } } } static string Decrypt(byte[] encryptedData, string key) { using (Aes aes = Aes.Create()) { aes.Key = Encoding.UTF8.GetBytes(key); aes.IV = new byte[16]; // 16 bytes Initialization Vector for AES encryption using (ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV)) { using (MemoryStream ms = new MemoryStream(encryptedData)) { using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read)) { using (StreamReader sr = new StreamReader(cs)) { return sr.ReadToEnd(); } } } } } }}在上面的示例中，我们使用了AES对称加密算法来加密和解密文本数据。首先，我们生成一个16字节的密钥和初始化向量（IV），然后使用这些密钥和IV来创建加密器和解密器。加密器和解密器将文本数据转换为字节数组，并对其进行加密和解密。最后，我们将加密后的数据和解密后的文本打印出来。
