????д????棺
????????Σ????????????????????????????????????C#????POST?????????????????????÷??????????????TLS 1.2 ???
?????????

???????????.NET FrameWork 4.0??????￡???????????????System.Net.SecurityProtocolType ????????????????????
???????????POST??????????????????е??????????????????????????1.0???

????????????о???????????????????????????1.2????????????????????1.2??
????ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;  //SecurityProtocolType.Tls1.2;
??????????????4.0??????????????????????????????????
namespace System.Net
{
using System;
[Flags]
public enum SecurityProtocolType
{
Ssl3 = 0x30??
Tls = 0xc0??
Tls11 = 0x300??
Tls12 = 0xc00
}
}