[emhart]

Combination locks that use letters/characters/non-numeral-glyphs have been around for an astoundingly long time, what's interesting about the word lock, though, is that they start with words, then make the dials.

https://www.google.com/patents/US6621405

The patent goes into detail - and is actually super easy/enjoyable to read - but the goal was to have a letter lock that maximized the number of real words that could be spelled from the available letters provided on the dial rings. So, a wordlist is generated under some parameters (such as word length) and then the rings are generated from that word list.

It's basically exactly what the author is doing, but in reverse.

The goal of the word lock was to increase the available keyspace of real words in a letter lock, thus increasing the security of those users who will buy a letter lock regardless. They do a number of other things right mechanically as well. Whether or not a bike lock is the best medium, I wouldn't say, but wordlock silently improved the security of a specific user base that greatly prefer convenience to security. That's awesome.

[norvig]

Very nice find on the patent, emhart. Thanks! It looks like the patent is the same as my `greedy_lock`, except that at each tumbler "the entire word list is scanned"; this is worse than scanning just the words that make it through the previous tumblers. Also, I was a noob at lock terminology; I should replace "dial" with "tumbler".

[emhart]

Thanks. I hadn't yet arrived at the greedy lock portion when I posted the above, but I finished the article soon after and absolutely loved it. The other thing worth noting is that while it sounds like there was some regional bias toward Fred Buns at your store, they should have different combinations of dials/letters on some of their locks. Also, also, some should be reconfigurable, which leads me to the challenge:

Optimal combination of dials in the circumstance that the dials can be rearranged.

& Don't sweat dial/tumbler, dial is more specific anyway, tumbler is the generic word.

[hackmiester]

Unfortunately, the locks are not configurable.

[kazinator]

The better ones certainly are. I have one.

When the lock is open, you can rotate an inner cylinder (not accessible while the lock is clasped) to a position which allows the outer rings of the dials to be moved to change the code.

Bought at a Canadian Tire store in Richmond, British Columbia. (See, even available in Canada.)

[hackmiester]

Oh, my mistake! Mine doesn't have that ability, and if you make that assumption, the article is accurate. I didn't know some could do that.

[jacquesm]

So, the best way to use a lock like that would be to pick a non word sequence. And regardless of the combinations these locks and all their derivatives are very easily opened even if you don't know the combination.

[kazinator]

I once destructively opened a friend's U-Lock in about 60 seconds. (The key broke, didn't have copy.)

I took a 10 dollar hack saw and sawed through the main bar of the lock (not the U).

It was like a hot knife through butter.