Help Locking the phone on restart/switch on(GT-P3100)


Hello friends,
I'm using a samsung galaxy tab2 p3100. Totally new with this. I want my phone to be locked when ever its being restarted or switching on, not when screen lock(that i prefer slide to unlock). I tried encrypting the device, but that cant be done without setting a password and once done i have to enter password every time i take phone(it get very annoying after sometime and waste of time). Is there any alternative?