Yesterday, our own Dan Goodin covered a clever new hack that uses a bit of calculation to reduce a well-known Master Lock exploit from 100 maximum attempts to just eight. Today, we put the hack to the test. Is cracking a Master Lock as simple as hacker Samy Kamkar makes it look if you have absolutely zero experience?

I bought a new Master Lock from a local drugstore last night and sat down with it this morning to see if I could pop it open without looking at the combination first. Using Samy's instructional video and a basic Web tool he designed, I timed my attempt at opening the lock.

The first few minutes seemed promising. I watched the video and began to replicate its instructions on the lock in my hands, but two of the steps proved trickier than they looked. The first and second "locked positions" were simple to find, but the third number I needed was a "resistant location" that was far more subtle. While I was supposed to note the one place where the lock caught each time as I spun the dial, it seemed to catch in multiple places even as I varied the pressure on the shackle. I took a guess and used the Web tool, which generated 16 possible lock combinations.

I tried to rule out half of these in the way shown on the video—testing which "third number" in the combination had more "give"—but this again seemed hard to measure. They felt almost identical. I took my best shot and then tried the remaining eight combinations.

None worked.

I watched the video again, refined my technique, and took another whack at the whole thing. This time I felt more confident about the "resistant location," but I still could see no difference between the two possible third numbers in the combination—so decided to try all 16 possibilities.

On my seventh attempt, I was startled as the lock popped open—as you can see in the video below.

Video by Jennifer Hahn

Gaming Editor Kyle Orland also took a whack at the challenge. Like me, he got it to work after some refinement:

After purchasing a brand new Master lock and watching the instructional video, I immediately ran into a problem: the lock first got stuck around the number "0." The instructions were unclear if that counted as one of the first "catch" locations, but I decided to run with it. The next catch was clearly around the number 3, so I jotted that down. Coming around clockwise, I thought I felt resistance around the number 12. I entered these numbers into the online tool and checked to see if the actual combination was among those listed on the website (rather than laboriously checking every possible combination). It seemed that every digit was off by at least one. Hmmm... Double-checking my results, I decided that the "resistant location" on the clockwise step was more like 12.5, rather than the 12 I had originally used. Entering this new result did generate the actual combination as one of the listed options.

Two other staffers had problems using older locks, however. Our video editor, Jen Hahn, tried the technique 10 times on a Master Lock from 1985 without success.

In my first 10 tests I let the first groove hit later, but the next 10 tries I eventually hit between .5 and 1.5 = 1. I think the video threw me off because his 0 was a bit off, so I thought mine was wrong. The second groove was between 4-5 even (no) but it looks more like 3.5-5 (worn gear?), next is 7-8 even (no), and the next was between 10.5-11.5 = 11. The resistant was more interesting. Clockwise I got 37, and counter-clockwise I got 5. In my first flawed test of 10 times, the first guess number was consistently wrong. In my second more accurate test of 10 times, the 3rd guess was consistently wrong. The middle guess always contained the solution number. I tried many combinations from the above results, but none gave me the correct combination. Clearly there’s something off in the worn dial or gears, or maybe mine just got better with age.

And writer Sam Machkovech couldn't get a "Sphero" Master Lock from the early 2000s to open, either.

But new Master Locks, even with total newbs spinning the dials, did pop right open after just a bit of fiddling.