[Nokinside]

Open source license does not mean giving up intellectual property rights. You can only license the work if you own the rights to the work.

MIT License starts with copyright notice:

    Copyright (c) <year> <copyright holders>

    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated 
    documentation files (the "Software"), to deal ....

[jwilk]

OTOH, you don't need to say "All rights reserved" to hold your rights:

https://en.wikipedia.org/wiki/All_rights_reserved