加密方式  AES-CBC-128

将解密方法改成如下

public  string Decrypt(string toDecrypt, string key){            if (string.IsNullOrEmpty(toDecrypt)) return null;            Byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);            System.Security.Cryptography.RijndaelManaged rm = new System.Security.Cryptography.RijndaelManaged            {                Key = Encoding.UTF8.GetBytes(key),                IV=Encoding.UTF8.GetBytes(key),                Mode = System.Security.Cryptography.CipherMode.CBC,                Padding = System.Security.Cryptography.PaddingMode.PKCS7            };            System.Security.Cryptography.ICryptoTransform cTransform = rm.CreateDecryptor();            Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);            return Encoding.UTF8.GetString(resultArray);}