Those software that claim can crack the password, I really doubt. I think they are using some hash calculation method which is some sort of brute-force. It will take years to crack if you have a well protected password like 8 characters long, using combination of small big alphabet and special characters.

If you don't want people to even see the contents of your rar file. Just double compress it. That means compress once without password. Then you will get a file called, eg filename.rar. Next, you compress that filename.rar with password protection and you will get another rar file maybe called filename-again.rar. So, when people open filename-again.rar, all they can see is filename.rar.

it is possible to to change the extension to whatever name u want.. not only wmv..
u can change it to xxxx.rar --> xxxx.lowyatnet
This also possible.. but some ppl can guess by trying chg the extension to various type, such as, mp3, zip, rar, iso and so on...

everything is hackable.

if u really want to secure ur file, maybe rename it to a weird extension like u winrar it to file.rar , then u rename the file to file.wmv

high chance people will just assume it is a corrupt file (unless theyre ppl like me)

double compression...?? great idea..
what bout triple compression with password each..
3password + 3 compress file...
it will take 3000 years.. lolz.. that time, the hacker already dead for sure