This question already has an answer here:
- Password Protect QGIS project 2 answers
Is it possible to lock a QGIS project file, so only I can open it with a password?
I work with a QGIS 2.18 version and I'm looking for a solution inside the QGIS software. in my map, i use only with regular layers and use not PostGIS. I red Password Protect QGIS project and it didn't answered my question.