Thursday, June 27, 2013

Locks and keys: Security and symbolism

So the Texas Legislature has finished the special session, accomplished nothing, and will do it all over again beginning July 1st. Grits can't begin to tell you how glad I am not to have a dog in any of the particular fights on the special session call. Better them than me.

Over the years, your correspondent has come to indulge the habit of finding some subject utterly unrelated to (or at least fundamentally different than) the topics covered on this blog to occupy my time and reading habits for at least a month or two following each legislative session: Helps clear the intellectual palate a bit and avoid burnout. This year, I decided to delve into an area that's directly related to many of the criminal-justice topics covered on this blog but which has nothing to do with the government, the courts, police, or prison policy. It's a subject that's fundamental to American and indeed human security but which few people outside of a tightly regulated profession ever think deeply about: locks and keys.

My interest began awhile back after we replaced the deadbolt on our front door. On a lark, I pulled out a screwdriver and began taking apart the old mechanism to see what was inside. Upon sliding out the cylinder where the key fits (perhaps a bit too abruptly), an array of springs and tiny pins flew everywhere, I picked them all up and tried to put them back into the slots, but not knowing the correct order, when I'd finished the key wouldn't work. I'd essentially re-keyed the lock, I later understood, and a locksmith in theory could have created a key for the new configuration. Though I threw the old lock away, the episode stuck with me and when the legislative session ended I dove headlong into the topic, seeking to learn more. Locks and keys, I realized, are all around us and arguably more essential to day-to-day security than police or jails. But for most people, they remain great mysteries.

Image via Design Junky
The deadbolt I took apart, like most mechanical locks in America, was a "pin tumbler" lock - a design which dates to antiquity and was popularized in modern times by Linus Yale and the Yale lock company. A pin tumbler lock may consist of 5-7 columns rising from the key slot, each with two small "pins" of different heights and a spring above them pushing the pins downward. (See the illustration at left of a cutaway lock.) When the key is inserted, the pins slide up until the top pins are all above the top of the cylinder, at which point you can turn the key. So the bumps on the key are precisely the right height to raise each pin to the necessary level, which is why the key wouldn't work when I put the pins back in the wrong order.

In his treatise, "Ancient Locks: the Evolutionary Development of the Lock and Key," Scott J. Klemm argues persuasively that the first pin tumbler locks date to ancient Greek and Roman times, not the Egyptians as is sometimes claimed in generalist literature on the subject. (Egyptians did develop the first locks with keys, says Klemm, but they were not pin tumbler locks.) Some of the best examples of ancient pin tumbler locks come from Pompeii, preserved under a mountain of volcanic ash. More than one hundred of these were photographed comprehensively by Italian locksmith Adalberto Biasiotti, Klemm wrote, but their examination revealed a fascinating discrepancy. All of Biasiotti's images show locks with multiple holes/columns, but "In each case the bolt has only a single pin of metal." Klemm wrote that "It would be strange indeed that all the pins deteriorated and only one pin in each lock survived. I think it's much more logical to conclude that in each of these cases only one pin was used." Another ancient lock from Palermo, he noted, included just two pins, but five holes where pins could potentially go.

Klemm suggested that, "Perhaps the most important reason" for using just one or two pins "was the structural weakness that would have resulted. Especially in smaller locks, five holes bored closely together would create very thin walls." But that seems unconvincing because the Roman locks described had extra holes drilled into them, they just weren't routinely utilized. Others have theorized that the rest of the pins may have been wooden and disintegrated thanks to time or fire, but Klemm correctly noted that "wooden pins would be no thicker than matchsticks and could be easily forced to their breaking point." To me, that hypothesis makes no sense, either.

Grits has a different theory as to why ancient locksmiths would only use one or two pins in early pin tumbler locks and it relates fundamentally to the nature of locks and our relationship to them. Locks are a mystery to most of us. We don't know how they work. One inserts a key, turns it, and the lock opens; turn it the other way, the lock engages. Most people today don't know any more about locks than that and it's a safe bet that purchasers of locks in ancient Roman times didn't either.

Back then, before the onset of mass production, each pin in a lock would have to be manufactured individually by hand, which must have been painstaking work. So using one pin instead of five would reduce the amount of labor spent making pins and springs by 80%. And as for the customer, who would know? If, once the lock were installed, it opened when a key was inserted and could not be opened without one (even if it's just one pin keeping the cylinder from turning), it would be all the same to them. And if some rare customer chose to take apart the lock, discover the missing pins, and knew enough about what they were looking at to complain, it would be simple enough to claim it was an error, pull a fully functional lock from behind the counter and appear to diligently correct the "mistake." It's not like there were consumer fraud protections on the books back then nor the sort of licensing strictures placed on locksmiths today. Anyway, odds are nobody ever noticed nor complained.

If Grits is right about why locks from Pompeii had just one pin, it speaks to the nature of locks and our relationship to them. For most of us, locks are a mystery. We know (or perhaps, assume) that they function but most of us have no clue how. Their outer housing conceals their inner workings and that opacity is part of their power. If one understands the inner workings, it's not that much more difficult to pick a lock with five pins instead of one. (Indeed, there's an entire "locksport" movement where amateurs pick locks competitively - go here and scroll down to see pictures from a locksport club at UT-Austin.)  But since most people don't have a clue how the lock functions at all, a single pin was sufficient in the vast majority of instances to provide security.

19th century Yale time lock inner workings (Source).
Even the most complex safe and vault locks ever produced can eventually be opened by someone who knows what they're doing. A wonderful book titled, "American Genius: Nineteenth century bank locks and time locks" demonstrated an almost unbelievable level of complexity and craftsmanship in 19th century safe and vault locks. But the authors conceded that "a conscientious thief could eventually open even state of the art locks" (p. 40) and that "no vault is wholly impervious to theft" (p. 22).

While some texts, like "Lock and Key: The secrets of locking things up, in, and out," speak of "the war between locksmiths and lockpicks," IMO that's not a completely accurate characterization because the act of lockpicking is not necessarily nefarious. An important job of a locksmith is to be able to open a lock when the key or combination has been lost. For example, when a homeowner loses their keys and is locked out of their house, a locksmith can get them in without breaking down the door. When granddad dies and it turns out he was the only one who knew the combination to the safe, somebody must be able to get inside. The same skillset is necessary for cops, repo services, realtors, and others (though often such occasional users will use a pick gun instead of learning to pick locks themselves). Indeed, with the advent of "locksport," lock picking is now a competitive hobby. As long as locks exist there will at times be a need - and for some, also a latent, compelling desire - to open them without key or combination. Not everyone who does so has criminal intent.

Grits' recent study of locks - particularly the most common, pin-tumbler type - has caused me to consider the possibility that their main function may frequently be more symbolic than a meaningful barrier to unwanted entry. The stronger and more elaborate the lock - like some of the astonishing bank vault locks that look like works of art forever hidden behind heavy metal doors - the more powerful the symbol. A locked door sends a message, "You are not supposed to go in here." As it turns out, many common locks can be picked or bypassed with relative ease. But even for those of us without such skills, a door could just as easily be kicked in, a side window may be broken: A determined person who wants in can generally get in. In practice, a lock at best slows them down, hopefully delaying a would-be intruder until other security measures kick in. But perhaps just as or more importantly, a lock functions as a symbol that says, "You don't belong in here." "Keep out." "The belongings inside are not yours." Amazingly, that alone is enough to stop most people, just like the one-pin locks in Pompeii were almost certainly adequate to ward off most intruders.

Locks function to a remarkable degree on that symbolic level, as a tangible token of the social contract. As a practical matter, there are many ways around them. Locks must sometimes be opened and their contents thus exposed in the normal course of human activity, giving ample opportunity in many cases to simply act while the lock is not engaged. Locks may be bypassed instead of picked, like a bike lock overcome by cutting the chain with bolt cutters. And of course, the most elaborate lock ever imagined may be easily opened by placing a gun to the head of the person with the key or combination.

Some years ago I heard a comedian - wish I could recall now who - suggest a novel solution to border security, recommending tongue-in-cheek that the government line the border with those plastic dividers you use on the grocery store conveyor belt to separate your food from the person in front of you. Those dividers, he pointed out, are universally respected. You never see anyone violate them. I'm coming more and more to think of locks and keys like the divider on the grocery-store conveyor belt. Even to the extent their function is symbolic, posing minimal barriers to a determined thief, it doesn't really matter. For the most part they're tremendously effective, probably preventing far more crime overall than does threat of punishment under the penal code.


doran said...

The best security lock for a home, in my opinion, is the sound (or better yet, the view through a window) of three or four viciously barking German Shepherds on the other side of the door.

Nice essay, Grits, and nicely distracting.

Texas Maverick said...

My 7-1/2# Teacup poodle thought he was a german shepherd and sounded like one so I kept the curtains pulled so you could'nt see him. LOL thx for the diversion and just for clarification, do you think we should use red or blue or black grocery dividers. Hee Hee. Enjoy the break, good advice.

Anonymous said...

youtube has a great video of how a combination lock works

Anonymous said...

A very thoughtful commentary.

You might enjoy reading of Richard Feynmen's books where he describes his adventures during the Manhattan Project in 'cracking' safes.

My Dad was a master aircraft mechanic. He spent the last 15 years of his working life on faculty in the Aviation Maintenance Department at Texas State Technical Institute in Waco. He used say "Locks are only there to keep the honest man out." Dad knew what he was talking about.

‘The Fishing Physicist’

DEWEY said...

Interesting essay. As a sidebar, when I was in the Texas Department of Corrup...oops... Corrections, when they had a problem with a lock, they didn't call a locksmith, they used a convict to fix it.

Anonymous said...

I've heard police officers say a lot of thefts could be prevented if people would close their garage doors and lock their cars.

Robert Frost wrote "Good fences make good neighbors." Same can be said of locks.

Anonymous said...

You do have a dog in this fight. You are PAYING for it.

Gritsforbreakfast said...

10:15, am I supposed to spend lots of time being angry because the elected governor exercised his constitutional power to call special sessions? Don't like it, beat him in an election. My taxes pay for lots of things I don't support, starting with volitional wars.

Otherwise, none of the issues on the call fall directly into this blog's wheelhouse and certainly nobody's paying me to follow them. Like I said, no dog in the fight.

mara said...

Locks. Passwords. Codes. Keys.
Picks. Hackers. Invasions. Leaks.
Security? HA!

Anonymous said...

Cool post! Very interesting! Thanks!

Anonymous said...

I have to disagree with the statement about locks only keeping the honest man out. It is right up there with the statement that if a burglar wants in, he will get in. Having been in trade for 40 plus years, it can just as easily be said that if you want to keep him out, you can. My example of that is the old Cleveland Federal Reserve round vault door. By making it 4 feet solid thickness of steel, the maker properly concluded that it would hold up against the 2 most dangerous entry tools of the time, nitro and the oxyacetylene torch.