BRADY HARAN: Hey there,
everyone.
Today's video is about
Richard Feynman--
a lot of people's favorite
scientist--
and safe breaking.
But I just wanted to point out
at the start that most safes,
or secure filing cabinets,
actually have one dial.
And if you've got a three
number combination, for
example, you'll turn that dial
in one direction, then the
other direction, and then back
in the other direction.
And that's how you open it.
But the mock up that we've
used in this video--
and it is a mock up,
I can assure you.
It's about as far from a
safe as you could get.
We've used three dials.
That kind of makes things a bit
more visual, a bit easier
to understand looking
at it in that way.
But in most cases, the sort of
safes we're talking about will
actually be using one dial.
I don't want to get all the safe
enthusiasts out there too
fired up and angry in the
comments section.
But for now, here's Professor
Bowley with his pretend safe
and the story of Richard Feynman
and his World War II
safe cracking.
PROFESSOR ROGER BOWLEY: I'm
talking about Feynman and how
he managed to crack safes when
he was working on the atomic
bomb project in Los Alamos
in the early '40s.
His wife had died.
So early in the 1940s,
his wife died.
And he was stuck in the
middle of Los Alamos,
not able to get out.
It was a sort of desert
area around there.
He was stuck with lots of other
theoretical physicists.
So he needed something
for amusement.
And as a hobby, he tried
cracking open all the safes in
Los Alamos.
Now, they had new, purpose built
safes with locks on them
made by the Mosler
lock company.
You can imagine 100 numbers
for this, 100 numbers for
that, 100 numbers for that--
a million, a million
possible settings.
And if you fiddle them around,
it'll take about five
seconds to do it.
So if you tried to crack
it, it will take
you about 60 days.
On the average, it'd be 30 days,
but 60 days if you screw
up and it takes the last
one to open it.
Well, Feynman was
a group leader.
So he was given one of these in
his office to keep all the
top secret files that he
might come up with.
So he knew how this worked
mechanically, because he
fiddled around with it.
He'd just fidget
with anything.
He wanted to know
how it worked.
And he found by trial and error,
suppose the number
should be 20, it was set at.
Actually, it started at 25,
and a lot of people didn't
change it from 25, naught, 25.
That was the default.
And if he wanted to crack the
safe, a lot of times, people
left it in the default setting,
because it's the
easiest one to remember.
Suppose he set it at 20.
Now, he found that if he tried
to set it at 20 and it opened,
he could also set it to 21
and it would open, or 22.
There was some slack on this.
This was not mechanically
perfect.
So there was a bit of tolerance,
plus or minus 2 on
every single number, which meant
that if you set it at
20, it could be 21 or
22 or 19 or 18--
and the same for this dial and
the same for this dial.
So now, if you go through all
the combinations, you only
have to do 3, 8,
13 and so on--
every fifth one--
to make sure you
cover them all.
Now, there are only 20 settings
for this, 20 for
that, and 20 for that.
So automatically, that's gone
down, oh, I can't do it.
Can you do it in your
head, Brady?
It's really quite difficult.
8,000 different settings--
now, that becomes doable
mechanically.
It will take you something
like 10 hours
working solidly overnight.
And you could do it.
And he could do that.
He worked out how to do it.
He found out other ways
of doing this.
He found that most people
will set a birthday, an
anniversary, some well-defined
date that--
I don't know, the Independence
Day in the United States of
America, whatever.
And it would not be an ordinary
number, because if
it's going to be, say, my
birthday, which is the 21st of
April if anybody wants
to send me presents.
There's the 21st.
04--
04 is there.
And I'm born in 1946,
which is down there.
So for the top one, which is the
days of the month, there
are typically 30 days
in a month.
So let's suppose there are
just 30 and never 31.
30 days in the month, you would
need to set it in six
different positions.
Now, for the months, there's 12
months in the year, so you
may need not two, but
three for that.
So now, we've got six settings
here, three settings there.
And for the year--
well, now, the year, if it's
some date, it's going to be
something in the past.
So how long back in the past
is somewhat arbitrary.
But suppose 45 would do,
and then it would be 9.
He was doing it 1942
or '43 or '44.
All right.
So the test would be somewhere
around there.
So 45 is a natural number to
look at, because then you
don't have to go back into
the previous century.
6 for this one, 3 for this
one, and 9 for that one.
And you multiply
them together.
And you get out 162.
So that's 162 different
settings.
Five seconds for each, 162--
that's 800 seconds.
It's about 12 minutes.
So he could go in and if
somebody had chosen one of
those dates, instead of having
8,000, he's got 162.
And he can do it
in 12 minutes.
On the average, it will be six
minutes, because he might be
reach it in the first
go or he might
reach it after 12 minutes.
But he would only require
12 minutes.
So he would go in and make a
big fuss of going into the
office and say, I'm not going
to show the secrets.
These are top secret stuff.
I don't want everybody
to know my secrets.
And he'd carry in a bag with
tools-- screwdrivers, picks,
all sorts of things that people
would think you crack
safes with--
shut the door, and in 12
minutes, he would do it.
He'd take a magazine
in with him.
Sometimes, he'd get it done
straight away and he'd do some
exercise and wait for 20 minutes
just to make everybody
believe it was tough
work doing this.
And then he'd come out with a
bit of sweat on his brow,
saying, that was hard work.
So those were the main
techniques that he used.
162 means that this isn't safe
and using your birthday or
anniversary is not safe.
But after that, he learned
another trick.
And he got the number
down to 20.
Out of all these million,
there were 20.
And it turns out that if you
open the safe and leave it
open, and there's a little
draw on the bottom.
And he goes into somebody
else's office.
He chats to them.
And the safe is open.
He fiddles with all the knobs.
And after two years of practice,
he got these two
sorted out by fiddling around
with the knobs when the safe
was open in somebody
else's office.
He'd go back afterwards--
and they don't realize he's been
doing this-- and writes
down these two numbers
in a little book and
says such and such.
So by the end of the
war, he could go
into anybody's office.
He's got the last two numbers.
There are 20 settings.
It takes him a minute
and a half to open
the safe, or less.
So he really has
to spin it up.
He has a reputation
of safe cracking.
And everybody thinks he knows
how to use picks.
But he's just used human nature,
the tolerance of all
this, and deviousness, just
to show how clever he was.
He was doing it just to show
how clever he was.
He was obnoxious.
He would like to be one
up on everybody else.
But there was a security
problem there.
And the guy who he shared a room
with was the guy who gave
the secrets of the bomb
to the Russians,
which is Klaus Fuchs.
He was a roomie of his.
BRADY HARAN: But for all his
showing off about safe
breaking, it turns out
the real spy was in
the room with him.
PROFESSOR ROGER BOWLEY: Yes.
But I don't--
well, yes.
When you look at this, now that
we live in worlds where
you have a little security
code for everything, this
seems unbelievably primitive--
phone hacking and everything
else going on.
But people weren't-- if you're a
scientist, you're not really
looking at the other guy next
door and wondering whether
he's letting all your
secrets out.
