I have Qt 5.4.0 on Windows 8.1 and Qt 5.4.2 on ArchLinux latest and get exactly the same result.

I have web-site which requires client SSL certificate. Server seems to be configured properly since execution of

Qt Code: 
  1. openssl s_client -connect myserver:443 -cert client.crt -key client.key
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prints

Qt Code: 
  1. Verify return code: 0 (ok)
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Also,

Qt Code: 
  1. curl --cert client.pem https://myserver/
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works just fine.

Server certificate is valid, browsers accept it, etc. Client certificate is self signed. Just in case, server is nginx and here is relevant config fragment
Qt Code: 
  1. listen                         *:443 ssl;
  2.  
  3.     server_name                    myserver;
  4.  
  5.     ssl                            on;
  6.     ssl_certificate                /etc/nginx/ssl/myserver.crt;
  7.     ssl_certificate_key            /etc/nginx/ssl/myserver.key;
  8.     ssl_dhparam                    /etc/nginx/ssl/myserver.dh;
  9.     ssl_protocols                  TLSv1.1 TLSv1.2;
  10.     ssl_ciphers                    "ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:ECDHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES256-GCM-SHA384:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:DES-CBC3-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!MD5:!PSK:!RC4";
  11.     ssl_prefer_server_ciphers      on;
  12.     ssl_client_certificate         /etc/nginx/ssl/ca.crt;
  13.     ssl_verify_client              on;
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But the following simplest Qt5 application
Qt Code: 
  1. #include <qcoreapplication.h>
  2.     #include <qfile.h>
  3.     #include <qnetworkaccessmanager.h>
  4.     #include <qnetworkconfiguration.h>
  5.     #include <qnetworkproxy.h>
  6.     #include <qnetworkreply.h>
  7.     #include <qnetworkrequest.h>
  8.     #include <qsslcertificate.h>
  9.     #include <qsslconfiguration.h>
  10.     #include <qsslkey.h>
  11.  
  12.     int main(int argc, char *argv[])
  13.     {
  14.         QCoreApplication a(argc, argv);
  15.  
  16.         QNetworkProxyFactory::setUseSystemConfiguration(true);
  17.  
  18.         QSslConfiguration sslConfiguration;
  19.  
  20.         QFile privateKeyFile("client.key");
  21.         privateKeyFile.open(QIODevice::ReadOnly);
  22.  
  23.         QFile certificateFile("client.crt");
  24.         certificateFile.open(QIODevice::ReadOnly);
  25.  
  26.         QSslKey privateKey(&privateKeyFile, QSsl::Opaque);
  27.         QSslCertificate certificate(&certificateFile);
  28.  
  29.         qWarning() << QSslSocket::supportsSsl();
  30.         qWarning() << certificate.serialNumber();
  31.         qWarning() << certificate.subjectInfo(QSslCertificate::CommonName);
  32.         qWarning() << certificate.expiryDate();
  33.  
  34.         sslConfiguration.setPrivateKey(privateKey);
  35.         sslConfiguration.setLocalCertificate(certificate);
  36.  
  37.         QNetworkRequest networkRequest(QUrl("https://server/"));
  38.  
  39.         networkRequest.setSslConfiguration(sslConfiguration);
  40.  
  41.         QNetworkAccessManager networkAccessManager;
  42.  
  43.         QNetworkReply* networkReply = networkAccessManager.get(networkRequest);
  44.  
  45.         QEventLoop loop;
  46.  
  47.         QObject::connect(&networkAccessManager, &QNetworkAccessManager::finished, &loop, &QEventLoop::quit);
  48.  
  49.         loop.exec();
  50.  
  51.         qWarning() << networkReply->error();
  52.         qWarning() << networkReply->errorString();
  53.  
  54.         delete networkReply;
  55.  
  56.         return a.exec();
  57.     }
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fails with the following console output on Windows
Qt Code: 
  1. QSslSocket: cannot resolve TLSv1_1_client_method
  2.     QSslSocket: cannot resolve TLSv1_2_client_method
  3.     QSslSocket: cannot resolve TLSv1_1_server_method
  4.     QSslSocket: cannot resolve TLSv1_2_server_method
  5.     QSslSocket: cannot resolve SSL_select_next_proto
  6.     QSslSocket: cannot resolve SSL_CTX_set_next_proto_select_cb
  7.     QSslSocket: cannot resolve SSL_get0_next_proto_negotiated
  8.     true
  9.     "01"
  10.     ("AA-00-00-00")
  11.     QDateTime("2035-06-21 21:41:13.000 UTC Qt::UTC")
  12.     99
  13.     "Unable to init SSL Context: "
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and the following console output on Linux
Qt Code: 
  1. true
  2.     "01"
  3.     ("AA-00-00-00")
  4.     QDateTime("2035-06-21 21:41:13.000 UTC Qt::UTC")
  5.     99
  6.     "Unable to init SSL Context: "
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If I remove "networkRequest.setSslConfiguration(sslConfigurati on);" I just get 400 error from server stating I need to send client certificate.

Adding "sslConfiguration.setPeerVerifyMode(QSslSocket::Ve rifyNone);" changes nothing.

I will be happy to get any advice what can be cause of Qt5 code failure.