ASP.NET“请求已中止：无法创建SSL / TLS安全通道”也会在配置的servicepointmanager中发生

Question

我正在尝试申请此图片：https://www.kamerstunt.nl/file/img/web/woning/9577323WenumWieselZwolseweg-142d_6.jpg 如果您在阅读本文时图像不再存在，则可能已将其删除，但您仍然可以查看相关的SSL证书。使用我的浏览器，我能够成功导航到页面，请求图像并查看有效的SSL证书。

我在这里查了一下：The request was aborted: Could not create SSL/TLS secure channel

所以我在代码中添加了该解决方案：

Dim imgRequest As WebRequest = WebRequest.Create("https://www.kamerstunt.nl/file/img/web/woning/9577323WenumWieselZwolseweg-142d_6.jpg")
Dim imgResponse As WebResponse
ServicePointManager.Expect100Continue = True
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls 
'//I also tried: ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls Or SecurityProtocolType.Ssl3
imgResponse = imgRequest.GetResponse()
Dim streamPhoto As Stream = imgResponse.GetResponseStream()

我试过了：

ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 Or SecurityProtocolType.Tls Or SecurityProtocolType.Tls11 Or SecurityProtocolType.Tls12

然后我得到错误： 'Tls12' is not a member of 'System.Net.SecurityProtocolType'和 'Tls11' is not a member of 'System.Net.SecurityProtocolType'

我还尝试更改注册表以允许窗口不用512位阻止DHE，并在HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman.

下添加ClientMinKeyBitLength和0x00000200（512）值

但它仍然失败了......为什么？

Answer 1

这是我使用的一个解决方案，它返回一个Stream ...您也可以修改它，使它返回一个字节数组，然后从该字节数组创建一个新的MemoryStream。也可以将其更改为网址，而不是要传递的字符串类型，但这取决于您。

Public Function GetRemoteStream(uRL As String) As MemoryStream
   Dim webClient As New WebClient()
   Dim imageBytes As Byte() = webClient.DownloadData(uRL)
   Dim mem As New MemoryStream(imageBytes)
   Return mem
End Function

使用示例

 Dim nStream As New MemoryStream
 nStream = GetRemoteStream(yoururlhere)

编辑请仔细阅读 ************************************* *******

在深入研究并进一步挖掘后，我找到了解决方案。该网站似乎已经放弃了对SSL＆amp; S的支持。 Tls11。

我开始了一个针对 4.5框架的新项目。然后我使用了这个SecurityProtocolType ...

 SecurityProtocolType.Tls12

<强>解决方案

将目标框架更改为： 4.5 并使用： SecurityProtocolType.Tls12 。 现在你的协议应该是这样的......

 ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12

另一个注意事项

我建议包装Stream，以便妥善处理。{1}}例如：

Using stream As Stream = imgResponse.GetResponseStream()
            Using ms As New MemoryStream()
                Dim count As Integer = 0
                Do
                    Dim buf As Byte() = New Byte(1023) {}
                    count = stream.Read(buf, 0, 1024)
                    ms.Write(buf, 0, count)
                Loop While stream.CanRead AndAlso count > 0
                'ms is your memory stream... as I take it you want the photo :)
            End Using
        End Using

这是我输出的证据......