vb.net - ASP.NET "The request was aborted: Could not create SSL/TLS secure channel"也与配置的 servicepointmanager 一起出现

Question

我正在尝试请求这张图片:https://www.kamerstunt.nl/file/img/web/woning/9577323WenumWieselZwolseweg-142d_6.jpg 如果在您阅读本文时该图像不再存在，它可能已被删除，但您仍然可以查看有问题的 SSL 证书。使用我的浏览器，我能够成功导航到页面、请求图像并看到有效的 SSL 证书。

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

所以我将该解决方案添加到我的代码中:

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:

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

但是我得到了错误: “Tls12”不是“System.Net.SecurityProtocolType”的成员 并且 “Tls11”不是“System.Net.SecurityProtocolType”的成员

我还尝试更改注册表以允许 Windows 不阻止具有 512 位的 DHE，并在 HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman 下添加值为 0x00000200(512) 的 ClientMinKeyBitLength .

但还是失败了……为什么？

Answer 1

这是我使用的一个返回 Stream 的解决方案...您还可以修改它，使其返回一个字节数组，然后从该字节数组创建一个新的 MemoryStream。您也可以将其更改为 url，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

示例用法

 Dim nStream As New MemoryStream
 nStream = GetRemoteStream(yoururlhere)

编辑请阅读 **************************************** *******

在对此进行调查并进一步挖掘之后，我找到了解决方案。该站点似乎已放弃对 SSL 和 Tls11 的支持。

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

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(protocol)应该是这样的......

 ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12

另一个笔记

我建议包装您的 Stream，以便妥善处理它。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

这是我输出的证明...