I release an app that working with simple http request for receiving json data and use naked tcp socket (not encrypted) for chat between user and admin and recently google play blocked my app on some devices like android 5.0.1 with this message "Blocked by Play Protect"
My question is : is this happened for using http and not encrypted tcp payloads ?
I can use ssl for http request but what can I do for the tcp chat ?
is making a diffie hellman key exchange encryption useful ?
Google Play Protect only blocks items it believes are malware. If your app is blocked by Google Play protect it is either malware, or behaving like it.
One option would be to try uploading your app to VirusTotal. This is a free service that lets anyone see what over 70 Anti-virus / anti-malware companies think of a file. You may get information from that about the app.
If these messages are not being seen by you yourself, but instead are coming in from user reports, then it is possible the thing being blocked is not in fact your app, but a modified or fake version of your app including malware.
If your app is published on Google Play, then it shouldn't be blocked by Google Play Protect. If this is happening then you should be able to ask for help with Play Console support. They can be contacted via the "?" help icon in the Play console.