Padlocks are locks that are usually hung from a hasp or other locking hardware. Their vulnerability is the shackle; in the case of the conventional brass padlocks, the shackle can be easily cut in seconds using a bolt cutter (unless the shackle is protected). This type of lock should never be used outdoors to protect valuables.
A strong padlock will lock in two positions (heel-and-toe) and the better ones will be ball-locking. For an explanation of these concepts and to understand how to specify and order padlocks, please click on Padlocks for Africa, a guide prepared by David Miller
Due to the prevalence of Crowbars used in burglaries, it is now more important than ever to use heavier stronger padlocks with heavy steel bodies, and shackles that are not easily reached or cut. They must be hung on heavy hasps, otherwise the burglar will cut the hasp!