Open a Master Padlock with a Beer can
Now I know that most people can claim to do anything while opening (and of course drinking) beer. But I just came across a great hack using the tin from a beer can to rig a shim that can open a Master Padlock. You know what a Master Padlock is right? They are the ones that are supposed to be master of lock security. Let also make the disclaimer on why people should know how easy it is to defeat your common lock.
Here is the story about unlocking (or picking) a Master padlock with a beer can - i-Hack website
Not to be over done I came across several other pages on other ways to open/pick a master padlock.... This page shows how to pick a Master padlock with a very simple metal shim - i-Hack shim padlock picker page
This article demonstrates how to open a Master padlock with a simple card - Pick a Common Master Lock With Your BART Card
To get really advanced, in a very lo-tech fashion, Engadget has an article on a special 'bump key' that will unlock the common cylinder that secures almost every home and office in less than 10 seconds. There is even a video of a 11 year old girl with no prior experience opening a lock in 11 seconds with the 'bump key' method. This tool has ben shown on CBS and many other media outlets.
This is a video demonstration of the use of a 'bump key' from the utube network.
Matt Blaze from the AT&T Labs/Research wrote Cryptology and Physical Security: Rights Amplification in Master-Keyed Mechanical Locks (pdf). Available on Matt Blaze's Crypto website. This paper shows "a very simple rights amplification attack that is effective against virtually all conventional master-keyed pin tumbler locks, including many so-called "high-security” products."