AES加密和解密

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

 namespace AES
 {
     public class AESEncryption
     {
         private static string strKey = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
         /// <summary>
         /// AES加密算法
         /// </summary>
         /// <param name="plainText">明文字符串</param>
         /// <param name="strKey">密钥</param>
         /// <returns>返回加密后的密文字节数组</returns>
         public static string AESEncrypt(string plainText)
         {
             try
             {
                 //分组加密算法
                 RijndaelManaged aes = new RijndaelManaged();
                 byte[] inputByteArray = Encoding.UTF8.GetBytes(plainText);//得到需要加密的字节数组

                 //设置密钥及密钥向量
                 aes.Key = Encoding.UTF8.GetBytes(GetMD5(strKey));
                 aes.IV = Encoding.UTF8.GetBytes(GetMD5(strKey).Substring(, ));
                 aes.Mode = CipherMode.CBC;
                 aes.Padding = PaddingMode.PKCS7;

                 ICryptoTransform transform = aes.CreateEncryptor();
                 byte[] buffer= transform.TransformFinalBlock(inputByteArray, , inputByteArray.Length);

                 //System.IO.MemoryStream ms = new System.IO.MemoryStream();

                 //CryptoStream cs = new CryptoStream(ms, aes.CreateEncryptor(), CryptoStreamMode.Write);

                 //cs.Write(inputByteArray, 0, inputByteArray.Length);
                 //cs.FlushFinalBlock();

                 StringBuilder ret = new StringBuilder();
                 foreach (byte b in buffer)
                 {
                     ret.AppendFormat("{0:x2}", b);
                 }
                 return ret.ToString();
             }
             catch
             {
                 return plainText;
             }
         }

         /// <summary>
         /// AES解密
         /// </summary>
         /// <param name="cipherText">密文字节数组</param>
         /// <param name="strKey">密钥</param>
         /// <returns>返回解密后的字符串</returns>
         public static string AESDecrypt(string cipherText)
         {
             try
             {
                 RijndaelManaged aes = new RijndaelManaged();

                 int len;
                 len = cipherText.Length / ;
                 byte[] inputByteArray = new byte[len];
                 int x, i;
                 for (x = ; x < len; x++)
                 {
                     i = Convert.ToInt32(cipherText.Substring(x * , ), );
                     inputByteArray[x] = (byte)i;
                 }

                 //byte[] inputByteArray = Encoding.UTF8.GetBytes(cipherText);
                 //设置密钥及密钥向量
                 aes.Key = Encoding.UTF8.GetBytes(GetMD5(strKey));
                 aes.IV = Encoding.UTF8.GetBytes(GetMD5(strKey).Substring(, ));
                 aes.Mode = CipherMode.CBC;
                 aes.Padding = PaddingMode.PKCS7;

                 ICryptoTransform transform = aes.CreateDecryptor();
                 byte[] buffer = transform.TransformFinalBlock(inputByteArray, , inputByteArray.Length);

                 //System.IO.MemoryStream ms = new System.IO.MemoryStream();
                 //CryptoStream cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Write);
                 //cs.Write(inputByteArray, 0, inputByteArray.Length);
                 //cs.FlushFinalBlock();
                 string strDecrypt = Encoding.UTF8.GetString(buffer);
                 return strDecrypt; 

             }
             catch
             {
                 return cipherText;
             }
         }

         public static string GetMD5(string str)
         {
             StringBuilder sb = new StringBuilder();
             foreach (byte b in System.Security.Cryptography.MD5.Create().ComputeHash(Encoding.UTF8.GetBytes(str)))
             {
                 sb.Append(b.ToString("X2"));
             }
             return sb.ToString();
         }

     }
 }