C#实现AES加密解密

 public class AESHelper
 {

     /// <summary>
     /// AES加密
     /// </summary>
     /// <param name="str">需要加密的字符串</param>
     /// <param name="key">32位密钥</param>
     /// <param name="iv">偏移</param>
     /// <returns>加密后的字符串</returns>
     public static string Encrypt(string str, string key, string iv)
     {
         Byte[] keyArray = System.Text.Encoding.UTF8.GetBytes(key);
         Byte[] toEncryptArray = System.Text.Encoding.UTF8.GetBytes(str);
         var rijndael = new System.Security.Cryptography.RijndaelManaged();
         rijndael.Key = keyArray;
         rijndael.Mode = System.Security.Cryptography.CipherMode.ECB;
         rijndael.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
         rijndael.IV = System.Text.Encoding.UTF8.GetBytes(iv);
         System.Security.Cryptography.ICryptoTransform cTransform &#