Robot & Frank : Brute force would not work

So the robot says that it takes between 4 seconds and 1 hour 43 minutes to crack a 3-number combination safe. That is complete rubbish. The 4 seconds is likely the estimate for opening the safe on the first try, this means it takes the robot 4 seconds to rotate the dial 3 times. 1 hour 43 minutes equals 6,180 seconds, divided by 4 gives 1,545 trials.

A combination lock dial usually scales between 1 and 100 (search "combination lock dial" on Google and you'll see). 3 number combination means at least 100 x 99 x 99 permutations (I'm assuming you can't have 3 identical numbers). That is 980,100 possible combinations, 634 times more combinations than the trials the robot can perform in the given time.

Ignoring that "little" problem and say the robot does brute force its way through the lock, another problem with spinning the dial so many times in such a short duration is heat generation. If every 3 trials span one single revolution (that is, the equivalent of rotating the dial exactly 360 degrees), that means 326,700 revolutions over the 103 minutes, which is over 3000 RPM. Imagine spinning the lock dial at that speed for over an hour. That thing will be so frigging hot the gears would probably expand and lock the entire assembly.

Even if the safe was using a high school combination lock (ie. 30 numbers), there will still be 25,230 possible permutations, 16 times more than the 1545 trials the robot can perform in the given time.

That robot might be able to cook and garden, but it sure as *beep* can't do basic math.

i hope your joking mate, cause otherwise you are a complete wanker!!!

Yes I'm a wanker because I can tell an egregious error that violates basic math.

What kind of moron is anti-intellect? I'm a nuclear engineer so you better hope I'm not joking when it comes to technical details. For someone whose uses a name of "you must learn", you sure aren't too accepting of learning.

Let me guess you watched Space Cowboys and screamed at the movie that's impossible to get someone in space in less than 60 days!" Or A guy that age couldn't impress a young hot woman (Donald Donald Sutherland's character at the bar). Dude relax if your putting that much emphasis into a FICTIONAL movie. You either seriously need to get laid or see a shrink..or both.

3 digit safe has exactly 1000 combinations. Permutations have nothing to do with it.

He is right. You are wrong. The only way to have 000 combinations is if you have 3 single-digits. The safe did not have only 10 values (0-9).

Most go up to at least 60. Three of those is 60*60*60 = 216,000. So yes, the upper bound should be 216,000 more than the lower bound. If the lower bound is 4 seconds, the upper bound should be 216,000 times 4 seconds, which happens to be exactly 10 days.

But that's just one example, with a 3-combination safe with a dial that goes up to the number 60. In combinatorics this is referred to as "60 choose 3". What you were describing (1000 combinations) is "10 choose 3".

-ClintJCL
http://clintjcl.wordpress.com/category/reviews/
http://www.flickr.com/photos/clintjcl

Why is it every nuclear engineer, brain surgeon and rocket scientist spend all their time posting things online? It's amazing how many of these people show up to argue about movies and tv shows

Because we read faster than the rest of you, so it's less of an effort. Nothing special, it's just more practice. Nerds read constantly, right?

My own reading speed was 1,200 words/minute, last time I tested myself. If you're an "average American", yours is about 200. OTOH, my fine motors skills stink and I can barely catch a thrown ballbecause that isn't something I ever practiced.

Your a wanker because you say things like "egregious error" and "anti-intellect".

For my latest movie reviews and news:http://www.hesaidshesaidreviewsite.com/

you must be fun at parties

Of course I'm fun at parties. I can calculate correctly the amount of beer necessary to sustain said party. Where as you probably underestimate like the robot in this film and end up having the worst party of all time.

Ha! Well done.


The Doctor is out. Far out.

cool story bro. he still opened it tho!!! bahahaha

No *bleep* Sherlock of course he opened it. Just because the script says the moon is square doesn't make it so. Or are you of the opinion that "if it happens on screen it must be true"?

i didnt hear them mention the moon once.

That's no moon, that's YO MAMA!

Cool story bro

haha nuclear engineer my A$$, someone who should know better to call it Maths, not "math" dumba$$, anyway, nice comeback for such an intelligent person. Newb

http://dictionary.reference.com/browse/math?s=t

Uh huh.

My retorts will only be as intelligent as the responses I got.

I didn't think the robot could open the lock in that short of time either. I just didn't bother to do the numbers. Thanks for proving that I was correct.

Playing scrabble with the Infantata! Here's a tip for you, let him win!

This thread is interesting.

But instead of brute forcing, it could have just listened for the gates to align and open it in 5 minutes.

But if you really wanted brute force, here's one:

http://www.kvogt.com/autodialer/

you see they dramatically reduce the time due to "forbidden zones" with the lock. maybe thats what the robot takes in consideration. do we actually know the lock type?

personally if i was going to have problems with this, i would have problems with the whole movie. such as how a robot that is so advanced like the robot that they would "forget" or not bother to block it from even attempting to brute force anything. it simply should be smart enough to decide.

though the concept is that the robot is the early models of a new robot, considering the woman's robot is the regular ones.

@savaslikesmovies

Interesting project. However the optimization only reduced one order of magnitude (ie. by 10) and the trial still took 21,000 attempts. 4 seconds (single attempt) by 21,000 attempts is still 23 hours.

Note also that this is a project developed by 2 MIT students with the aid of laptops and detailed technical knowledge, not a senile octogenarian who confuses his robot with his son wearing an astronaut helmet.

The robot in the video does dial the lock faster than the movie robot however, averaging 2 seconds per combination (11 clicks in the 26 second video). The site doesn't detail exactly how many is "a few hours". 21,000 attempts at 2 second average is still over 11 hours. The article might have misrepresented the robot's speed.

The lock used in their project is a Sargent and Greenleaf 8400, with a face dial of 0 to 99, culminating in 1,000,000 (one million) possible permutations as advertised on their own site (http://www.sargentandgreenleaf.com/MC-8400.php). This is the same number used in my calculations in the topic post.

Point is, there is NO WAY the robot can "brute force" its way into a safe as depicted in the film within the time frame given by the robot. Modern cryptology (including physical safes) are designed to combat brute force entry specifically because of the computational power we have today. This might change if and when quantum computing becomes a practical reality, but that doesn't seem likely any time soon.

no i think it reduced it more than that. from a comment on that page:

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for the 8400 lock: no numbers between 35 & 55 for the last number, no numbers ending in 0 or 5, and no rising or falling sequences.

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unless the comment is incorrect, which i haven't bothered to check. you can find more about "forbidden zones", here: http://www.crypto.com/papers/safelocks.pdf

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The lever-fence design is subject to somewhat anomalous behavior if the combination of the last wheel is set
too near the point at which the nose enters the drive cam gate. Usually, the lever nose will become trapped
in the cam gate, preventing the bolt from being re-locked. More rarely, the lock will fail to open altogether.
This is the reason that the range of numbers allowable for the last combination is restricted, avoiding those
that would position the last wheel gate too close to the cam gate. This region of the dial is usually called the
forbidden zone, and applies only to the last number of the combination.

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anyway those mit guys are very vague with their numbers. the safe has a finite amount of combination so it 100% possible to brute force a safe, this isn't news. the question is how long, but they seem to not even answer the only question that matters. anyway, why are you comparing frank to the mit students, it's not as if frank built the robot or even programmed it.

once you build the fastest "robot", then the only thing slowing you down is the safe, and that we don't know of.

the writer probably heard of brute force from somewhere and felt it would sound cool in the movie. obviously they have no idea about why mechanical safes are no longer used. simply because you can get in them in like 5 minutes, just by detecting the gates.

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no i think it reduced it more than that. from a comment on that page:

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Well that's irrelevant as I pointed out, even at 2 seconds per attempt (as shown in video), the safe will still take over 11 hours to crack.

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why are you comparing frank to the mit students, it's not as if frank built the robot or even programmed it.

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Because Frank instructed the robot to crack the safe. Unless the robot comes pre-packaged with a safe-cracking subroutine, ANY information it has probably came from Frank. Therefore Frank must have detail knowledge of the safe mechanism in question.

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the writer probably heard of brute force from somewhere and felt it would sound cool in the movie. obviously they have no idea about why mechanical safes are no longer used. simply because you can get in them in like 5 minutes, just by detecting the gates.

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But mechanical safes are still being used. And there's nothing stopping manufacturers from making a hybrid safe where the combination actually dials a digital encryption box, negating the whole "crack by listening" thing.

I don't think the writers thought "brute force" would sound "cool" and put it in the film. The writers probably thought "robots can do stuff real fast so let's make it brute force its way into a safe". Unfortunately they lack the very basic understanding of high school statistics necessary to avoid the kind of stupidity shown in the film.

I find more and more movies these days not only ask me to suspend my disbelief, but also suspend basic logic, reasoning, science, and more or less everything else. Take for example "Taken 2" where our hero asks his daughter to draw a circle using circumference

This thread is interesting, but I want to point out a mistake you are making. The robot is shown to have mobile connectivity. It is able to call the son without using a phone. This implies he is also connected the internet. It can easily Google information about safe picking and find things such as this MIT project. So, Frank would not be the only source of information for the robot.

Ah! Nice logic.
However, you have forgotten one thing: This was a FUTURE safe! The movie took place in the FUTURE!!!! SO: who's to say that these future safes don't have the problem with heat & expanding gears?
Also - maybe the robot was smart enough to apply an algorithm to eliminate obvious duplicate or fake combinations? IE: chances are the combination wasn't 1-2-3, so maybe he didn't need to try THAT one?
See? THE FUTURE!!! It will mess you up!!!!

r u a robot?

The OP really needs to get laid.

In one of his recent posts on another threat he literally wrote "I watch too much porn"

If you want to get realistic about the movie Frank left a bunch of DNA evidence when he was robbing the house. Presumably in the future they will be even better at finding it at robbery sites and matching it to someone, especially if they have a prior criminal record. (The same can be said about the stealing of the book, but Frank goes to the library a lot, so he could argue that's where his DNA came from. He had never officially been in the house he robbed, though.)

In addition, the police show no warrants whatsoever when they enter Frank's home multiple times. (Finding a few soaps does not constitute "probable cause"; all it means is Frank had a few soaps. And the "probable cause" is what they need to get the warrant, not to enter the home illegally.)

Also, the presence of the man who was robbed would not be allowed at Frank's house.


"My name is Paikea Apirana, and I come from a long line of chiefs stretching all the way back to the Whale Rider."

Here is the glaring problem with your theory:

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The 4 seconds is likely the estimate for opening the safe on the first try, this means it takes the robot 4 seconds to rotate the dial 3 times.

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This is a deplorable supposition on your part. It is not a scientifically-verifiable speed restriction of the robot's ergonomic dexterity. It is you arbitrarily making a bone-headed assumption based on the robot's temporal estimation. We do not know how fast the robot can manually spin anything. We do not know the robot's statistical algorithm nor its computational margin of error when calculating the chronological range of a job completion. The robot can not spin the dial at a constant speed because of the bidirectionality of motion involved.

So unless you have some time trial averages on this particular automaton doing this particular task, then you are simply bloviating for your own edification.

Also, you are postulating your "heat" theory on known mechanical design. This film is set in the (near) future - one with obvious technological advances beyond current application. The safe dial innards could be a hitherto unpatented component with a frictionless internal construction. Again, if you don't have any peer-reviewable data to back up your statements, your only evidence is your limited understanding of high school mathematics.

P.S. The movie is also fiction and not the real world - you know that stuff presently outside the one little window in your mom's basement.

Game, set, and match.



Working in the movie business since -92

What s/he said. This thread is hilarious!

Should you stay for the credits? Check www.mediastinger.com!

I didn't do the math, but I could tell the moment he said how long it would take him that it couldn't be correct. But don't let people here get you all riled up, that's the nature of the message board; somebody is going to call you stupid no matter how legitimate your post is. And the reason it didn't take him forever to open the safe isn't the same reason that a moon can be square in a movie, because he almost assuredly would have opened it in real life in less time than the maximum time figured (not figuring in your very-plausible gear melting theory), unless the odds were heavily stacked against him, and the correct combination was the very last one he tried.

But all said and done, you are absolutely correct, and it seems like that would have been caught early on in the script writing process.

He is not absolutely correct. This is a work of fiction with a futuristic setting whose unknown technology he is criticizing with contemporary conventions based on seriously flawed suppositions.

Science fantasy - no matter how slight - needn't conform to modern science fact.

Here's what I want to know. How come no one has mentioned Robot's "disguise"? That black cape was hilarious and cute.


Im the Alpha and the Omoxus. The Omoxus and the Omega

The cape was a sweater draped over him but looked like a cape. I think they were trying to cover up all that whiteness so he wouldn't be so visible at night time.

It was funny.

Learn to loosen up a little as this is only fiction i.e. not meant to be real. If you take things too seriously you might end up been single forever!


My Voting history is secret;)

the calculation is ridiculous and retarded cuz normal people dont post a thread like this

Now try telling us what your post has to do with the film.


http://www.rateyourmusic.com/~JrnlofEddieDeezenStudies

Interesting point.

My friend was a locksmith. I remember he told me once that not all combinations were possible, depending on the type of lock. Only certain combinations were possible. For example, you wouldn't be able to have a combination that's like X - X - Y and there are other ranges.



Show me the holes!

I think you are forgeting some details Let's say we have a 4 digits safe. The dial has 1 at the top, 2 at the right, 3 at the bottom and 4 at the left. I need to find a 2 digits combination, and my first guess will take 0.720 seconds. According to you it will take me 11.52 seconds to get every possible combination. However the safe doesn't reset after every pair of numbers, I will not have to input: 11-12-13-14-21-22-23-24-31-32-33-34-41-42-43-44

Instead I could use: 1121314223243441 and I have every possible combination.

So, if my first guess took me 0.720 seconds, you might think that every turn takes 0.360 secs, therefore the entire sequence will take 6.120 seconds. But lets say that, for the first pair of numbers (11), I have to turn the dial 360, first clockwise, second counter-clockwise, that's why it takes me 0.720 seconds, 1 millisecond per degree. For the next number I will need to turn it just 90 CW, then 90 CCW, 180,180, 270, etc. Total number of degrees or milliseconds: 3960.

Not 11.52s as you would guessed, but 3.96s

If we take into account the previously mentioned document (http://www.crypto.com/papers/safelocks.pdf), the safe might have only 22,330 "good" combinations If 4 seconds is not an average, but the time needed for the first permutation, and if that is the one that takes more time, we can assume that each turn takes an average of 0.667s (a Gaussian assumption, lol). According to my empirical theory, each turn will throw a new permutation, so it will take 22,332 turns to get all the possible combinations. That's still more that 4 hours, that's why I'm suspecting Robot knew something that we don't!

Accurate or not, I loved the movie!

Sorry for my english.

Your thread title is wrong.

Brute force WOULD work - it would just take longer than was stated and depicted in the film.

Maybe it takes the robot 1/2 second to initially get his arm & hand in position to start, 1/2 second to actually dial three numbers, and then, once the correct numbers have been dialed, 3 seconds to rotate the arm & then pull the door open.

It would thus still take 4 seconds to open the safe if the first guess were correct, but 1/8th the total time calculated here, by whomever is correctly calculating the number of dials needed, to go through every possible combination.

(And I really, REALLY don't care who's correct!)



A little knowledge is a dangerous thing.

Oh, and I bet the OP never gets laid!

Ever.

So, has anyone actually figured out the correct time?

Unless you know the type of lock, you can really never know the real answer.
The OP has a point in saying you couldn't crack the lock using the brute force method. It would obviously take too long. Therefore, the Robot obviously used another method. The Robot must have exaggerated when he was telling Frank he was using a brute force method. He must have used some short cuts. short cuts that are probably too complex or too boring to explain to Frank or the audience so he just says he is using a brute force method. The Robot is able to lie and exagerate as seen in the film. He is even able to steal just to make his master feel better. Cracking locks for him is child's play.

The door was on a second floor balcony, or something.

The various posts about combination dials having fewer available combinations than they appear to is spot on. For your typical Master lock on your school locker, around 1/3rd as many numbers as it seems. Try it. Enter a combination off by exactly one on every single value and it'll work.

They skipped a bit, but yes they clearly had additional knowledge of the type of safe. And: this goes great with the absolutely true statements Frank made several times about no security being perfect, everyone in the industry knowing that, and you just delay entry and make best guesses. Plus, the victim wasn't a security expert, so just had some consumer safe. Easy.

OTOH, would have been cool if, because it's a vaguely medical robot, it had enough sensors to listen to the lock mechanism and open it basically immediately instead.