由于以下错误消息,我们无法使用WebRequest连接到HTTPS服务器:

请求被中止:无法创建SSL/TLS安全通道。

我们知道服务器没有有效的HTTPS证书,但为了绕过这个问题,我们使用下面的代码,我们从另一个StackOverflow帖子:

private void Somewhere() {
    ServicePointManager.ServerCertificateValidationCallback += new RemoteCertificateValidationCallback(AlwaysGoodCertificate);
}

private static bool AlwaysGoodCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors policyErrors) {
   return true;
}

问题是服务器从未验证证书,并出现上述错误而失败。有人知道我该怎么做吗?


我应该提到的是,我和一个同事几周前进行了测试,它运行得很好,与我上面写的类似。我们发现的唯一“主要区别”是,我用的是Windows 7,而他用的是Windows XP。这会改变什么吗?


当前回答

另一种可能是正在执行的代码没有所需的权限。

在我的例子中,我在使用Visual Studio调试器测试对web服务的调用时得到了这个错误。Visual Studio没有以管理员身份运行,这导致了此异常。

其他回答

system.net.webeexception:请求被中止:无法创建 SSL/TLS安全通道。

在我们的例子中,我们使用的是软件供应商,所以我们没有权限修改。net代码。显然。net 4不会使用TLS v 1.2,除非有变化。

我们的解决方法是将SchUseStrongCrypto键添加到注册表中。您可以将下面的代码复制/粘贴到扩展名为.reg的文本文件中并执行它。它是我们解决问题的“补丁”。

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001

以上大多数答案都提到了会话算法或密钥交换算法。

在我的情况下,两者都是OK的,问题是在服务器的证书哈希算法,在客户端PC上没有启用。

我在应用程序的配置中添加了一个部分。

<system.diagnostics>
    <trace autoflush="true" />
    <sources>
        <source name="System.Net">
            <listeners>
                <add name="System.Net" />
            </listeners>
        </source>
        <source name="System.Net.Sockets">
            <listeners>
                <add name="System.Net" />
            </listeners>
        </source>
        <source name="System.Net.Cache">
            <listeners>
                <add name="System.Net" />
            </listeners>
        </source>
    </sources>
    <sharedListeners>
        <add
            name="System.Net"
            type="System.Diagnostics.TextWriterTraceListener"
            initializeData="System.Net.trace.log"
        />
    </sharedListeners>
    <switches>
        <add name="System.Net" value="Verbose" />
        <add name="System.Net.Sockets" value="Verbose" />
        <add name="System.Net.Cache" value="Verbose" />
    </switches>
</system.diagnostics>

然后log中的错误让我得到了这个解

只要这是一个相对“活”的链接,我想我会添加一个新的选项。这种可能性是由于Poodle攻击的问题,该服务不再支持SSL 3.0。看看关于这个的谷歌语句。我在使用多个web服务时同时遇到了这个问题,并意识到一定发生了什么事情。我切换到TLS 1.2,一切都恢复正常了。

http://googleonlinesecurity.blogspot.com/2014/10/this-poodle-bites-exploiting-ssl-30.html

In my case, I was running under Visual Studio 2022. Time and time again I was getting this error. Going through the code I saw that it retrieved the certificate just fine. Security was set to TLS1.2, both answers above. For whatever reason, running Visual Studio as Administrator made it work! Maybe someone can explain to me how the code retrieved the certificate from the store just fine. I could see it and all the properties. Why in the name of this world would it not process the request unless I run VS in admin mode???

The top-voted answer will probably be enough for most people. However, in some circumstances, you could continue getting a "Could not create SSL/TLS secure channel" error even after forcing TLS 1.2. If so, you may want to consult this helpful article for additional troubleshooting steps. To summarize: independent of the TLS/SSL version issue, the client and server must agree on a "cipher suite." During the "handshake" phase of the SSL connection, the client will list its supported cipher-suites for the server to check against its own list. But on some Windows machines, certain common cipher-suites may have been disabled (seemingly due to well-intentioned attempts to limit attack surface), decreasing the possibility of the client & server agreeing on a cipher suite. If they cannot agree, then you may see "fatal alert code 40" in the event viewer and "Could not create SSL/TLS secure channel" in your .NET program.

The aforementioned article explains how to list all of a machine's potentially-supported cipher suites and enable additional cipher suites through the Windows Registry. To help check which cipher suites are enabled on the client, try visiting this diagnostic page in MSIE. (Using System.Net tracing may give more definitive results.) To check which cipher suites are supported by the server, try this online tool (assuming that the server is Internet-accessible). It should go without saying that Registry edits must be done with caution, especially where networking is involved. (Is your machine a remote-hosted VM? If you were to break networking, would the VM be accessible at all?)

在我公司的案例中,我们通过注册表编辑启用了几个额外的“ECDHE_ECDSA”套件,以修复当前的问题并防范未来的问题。但是如果你不能(或不愿意)编辑注册表,那么很多变通办法(不一定漂亮)就会出现在你的脑海中。例如:你的. net程序可以将它的SSL通信委托给一个单独的Python程序(它本身也可以工作,因为同样的原因,Chrome请求可能成功,而MSIE请求在受影响的机器上失败)。