用C#窗体实现AES加密和解密

首先，需要引入System.Security.Cryptography命名空间。

以下是C#窗体实现AES加密和解密的示例代码：

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Windows.Forms;

namespace AesDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnEncrypt_Click(object sender, EventArgs e)
        {
            try
            {
                // 获取密钥和向量
                string key = txtKey.Text.Trim();
                string iv = txtIV.Text.Trim();
                byte[] keyBytes = Encoding.UTF8.GetBytes(key);
                byte[] ivBytes = Encoding.UTF8.GetBytes(iv);

                // 获取明文
                string plaintext = txtPlaintext.Text.Trim();
                byte[] plaintextBytes = Encoding.UTF8.GetBytes(plaintext);

                // 创建AES加密器
                using (Aes aes = Aes.Create())
                {
                    aes.Key = keyBytes;
                    aes.IV = ivBytes;

                    // 创建加密流
                    using (MemoryStream msEncrypt = new MemoryStream())
                    {
                        using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, aes.CreateEncryptor(), CryptoStreamMode.Write))
                        {
                            // 将明文写入加密流
                            csEncrypt.Write(plaintextBytes, 0, plaintextBytes.Length);
                            csEncrypt.FlushFinalBlock();

                            // 获取加密结果
                            byte[] ciphertextBytes = msEncrypt.ToArray();
                            string ciphertext = Convert.ToBase64String(ciphertextBytes);

                            // 显示加密结果
                            txtCiphertext.Text = ciphertext;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void btnDecrypt_Click(object sender, EventArgs e)
        {
            try
            {
                // 获取密钥和向量
                string key = txtKey.Text.Trim();
                string iv = txtIV.Text.Trim();
                byte[] keyBytes = Encoding.UTF8.GetBytes(key);
                byte[] ivBytes = Encoding.UTF8.GetBytes(iv);

                // 获取密文
                string ciphertext = txtCiphertext.Text.Trim();
                byte[] ciphertextBytes = Convert.FromBase64String(ciphertext);

                // 创建AES解密器
                using (Aes aes = Aes.Create())
                {
                    aes.Key = keyBytes;
                    aes.IV = ivBytes;

                    // 创建解密流
                    using (MemoryStream msDecrypt = new MemoryStream(ciphertextBytes))
                    {
                        using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, aes.CreateDecryptor(), CryptoStreamMode.Read))
                        {
                            // 读取解密结果
                            byte[] plaintextBytes = new byte[ciphertextBytes.Length];
                            int bytesRead = csDecrypt.Read(plaintextBytes, 0, plaintextBytes.Length);

                            // 显示解密结果
                            string plaintext = Encoding.UTF8.GetString(plaintextBytes, 0, bytesRead);
                            txtPlaintext.Text = plaintext;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
    }
}

在窗体上添加三个TextBox控件和两个Button控件，分别命名为txtKey、txtIV、txtPlaintext、txtCiphertext、btnEncrypt和btnDecrypt。用户输入密钥、向量和明文，点击“加密”按钮进行加密，点击“解密”按钮进行解密。加密和解密过程中，采用AES算法进行加密和解密，使用Base64编码将密文转换为字符串。