C# AES 加解密类

using System;
using System.Linq;
using System.Security.Cryptography;
using System.Text;


public class AES
{
	public static String Key = "www.02405.com";

	/// <summary>
	///  AES 加密
	/// </summary>
	/// <param name="str">明文（待加密）</param>
	/// <param name="key">密文</param>
	/// <returns></returns>
	public static string AesEncrypt(string str)
	{
		if (string.IsNullOrEmpty(str)) return null;
		Byte[] toEncryptArray = Encoding.UTF8.GetBytes(str);

		RijndaelManaged rm = new RijndaelManaged
		{
			Key = Encoding.UTF8.GetBytes(Key),
			Mode = CipherMode.ECB,
			Padding = PaddingMode.PKCS7
		};

		ICryptoTransform cTransform = rm.CreateEncryptor();
		Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
		String HexString = String.Join("", resultArray.Select(item => item.ToString("X2"))).ToUpper();
		return HexString;
	}
	/// <summary>
	///  AES 解密
	/// </summary>
	/// <param name="str">明文（待解密）</param>
	/// <param name="key">密文</param>
	/// <returns></returns>
	public static string AesDecrypt(string str)
	{
		Byte[] toEncryptArray = parseHexStrToByte(str);

		RijndaelManaged rm = new RijndaelManaged
		{
			Key = Encoding.UTF8.GetBytes(Key),
			Mode = CipherMode.ECB,
			Padding = PaddingMode.PKCS7
		};

		ICryptoTransform cTransform = rm.CreateDecryptor();
		Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
		return Encoding.UTF8.GetString(resultArray);
	}


	/// <summary>
	/// 字符串转字节
	/// </summary>
	/// <param name="hexStr"></param>
	/// <returns></returns>
	public static byte[] parseHexStrToByte(String hexStr)
	{
		if (hexStr.Length < 1)
			return null;
		byte[] result = new byte[hexStr.Length / 2];
		for (int i = 0; i < hexStr.Length / 2; i++)
		{
			String Char = hexStr.Substring(i * 2, 2);
			result[i] = Convert.ToByte(Char, 16);
		}
		return result;
	}
}