下面是解密方法
/// <summary>
    /// RSA解密
    /// </summary>
    /// <param name="content"></param>
    /// <returns></returns>
 public static string DecryptRsa(byte[] bytes)
    {
        try
        {
            UnicodeEncoding byteconvert = new UnicodeEncoding();
            //byte[] bytes = Encoding.UTF8.GetBytes(content);
            RSACryptoServiceProvider rsac = new RSACryptoServiceProvider();
            StreamReader reader = new StreamReader(@"F:\Security\study\PublicKey.xml");
            string PrivateKey = reader.ReadToEnd();
            rsac.FromXmlString(PrivateKey);
            reader.Close();
            //rsac.ImportParameters(privateKey);
            return byteconvert.GetString(rsac.Decrypt(bytes, true));
        }
        catch (Exception ex)
        {
            return ex.Message;
        }
    }