Rooting Samsung Galaxy Pocket i have an android Device (Samsung Galaxy Pocket S5300) which i want to root, because i have used Ubuntu on my PC and Notebook for five or six years and i am familiar with doing different maintainace there using root, so i want to have a way to use root-privilleges on my smartphone too. I dont have a lot of experience in delevoping smartphone applications and rooting smartphones, so i need a bit help.

After a bit reading, i read that i should download an update.zip file, which i should select in the recovery mode.

I read this blog: http://forum.xda-developers.com/showthread.php?t=2365697 where they say i should download an update.zip from mediafire. I downloaded it to my PC and had a look into it and could found the various binaries that i need to be installed (su, busybox, superuser.apk etc.)

Now i have a question: do i really need to download an update.zip from mediafire, where i don't know what it comes from? The reason I'm worried is that i don't know who has created it and have no really posibility to check if the binaries i will execute are not compromised and have no viruses etc... i am a bit scared to execute binaries somewhere form the web (with root pivilleagues) where i don't know if they are to be trusted and to be sure that they are no virusus, spyware etc...

Thank you.
Whether the file is on mediafire or xda, you still run the risk of a user putting up a bad file (whether maliciously or incompetently). You have to trust someone unless you decide to make your own rom from scratch. 

You could always open the update.zip file and do a cursory look at its contents. And if the poster has a good history, that gives points in their favor. Many posters on xda host their files on external download tools like mediafire; it doesn't inherently make the file more suspicious.