With the May Update 2019, Windows is showing an alert in case you connect to an insecure network. Here's what to do
If you've managed to install the Windows 10 May Update without any major problems and are able to use the 1903 version of Microsoft's operating system, at the maybe you may have found something new in the bottom right corner of the screen, that is, in the Notification Center: a message telling you that your Wi-Fi network is not secure.
Many users, in fact, have reported that the new Windows 10 shows them the following message: "This Wi-Fi network uses an old security standard that has been outdated. We recommend that you connect to a different network." Connecting to the discouraged network is still possible, as in the past. But why does Windows now send this message? What has changed in your network compared to before you installed May Update? Absolutely nothing, but if Windows tells you that your network is not secure, it has a point. On the contrary: This time Microsoft made the right call, and the message it sent you can really help you improve the security of your Wi-Fi network.
Why your network isn't secure
As the message sent by Win 10 itself says, it's a security standards issue. All Wi-Fi networks can (and should) be protected by a password that is encrypted by the router using an international standard. Over the years, there have been several standards: WEP, WEP-TKIP, WPA, WPA2 and, as of a few months ago, WPA3. None of them is perfect and faultless: even the latest WPA3 has been accused of being easily hackable.
But the further back we go with time, the less secure the encryption standard is.
If Windows 10 tells you that your network is not secure, then it's very likely that your router is set to use WEP encryption (which stands for Wired Equivalent Privacy, a standard dating back to 1999) or WEP-TKIP, which is an evolution that doesn't improve security much. WEP is an encryption standard with only 64 bits (later increased to 128 bits, against 256 bits of the three WPA standards) and that is full of flaws: in 2005 the FBI demonstrated to be able to violate WEP encryption in a few minutes.
How to make your Wi-Fi network more secure
If the security problem is in the protocol, then change the protocol. Most of the routers we find in our homes are compatible with several standards, from WEP to at least the first generation WPA. All you have to do is enter the router's configuration page, go to the section dedicated to Wi-Fi networking and look for a setting such as "Security Mode", "Encryption" or "Security". Each router manufacturer calls it differently, but when you open the drop-down menu you'll always find the different encryption standards already described.
If the standard you have set is WEP, change it immediately to a more advanced one: the ideal is a recent WPA, even better if with AES (Advanced Encryption Standard). If you see the alert message when you try to connect to a public network, you cannot change the router settings, so you should avoid connecting to this network.