Silk Road forums

Discussion => Newbie discussion => Topic started by: Dickens018 on February 15, 2013, 10:09 am

Title: A simple security puzzle.
Post by: Dickens018 on February 15, 2013, 10:09 am
An old puzzle, but I found it good for getting people to think about security.  I suspect this will be easy for many of you.     

You are given access to a room,  and your mission is to select a card from a deck cards and hide somewhere in the room so your selection remains secret for 60 minutes. You are told that the price of failure is extremely negative.

  Upon entering the room,  you see an open safe,  an a quick glance reveals no apparent video cameras and a door you can close.Sitting on the safe is  an unopened deck of cards, a knife,  a book,  a box of latex gloves,   a small, clean towel and a glass of water.  You walk in and close the door,  noticing a Count-down timer over the door that has started counting down from 5:00, 4:59,4:58..

How do you select the card and hide it so your choice remains hidden for at least one hour, and avoid the unpleasant penalty clause?
Title: Re: A simple security puzzle.
Post by: DotJPG on February 15, 2013, 10:20 am
open the deck with the knife genitally, slipping it into the open, but un touched deck and moving it up and down slowly so some of the cards become protruded a little bit, pick up the deck with my thumb and pointer finger with my left hand so that the cards are facing right. move the deck so only the card that is sticking out the most is resting on top of the left side of the safe (assuming im looking at the safe head on). stab the card that is most sticking out with the knife and slide it out and pack the rest of the cards down with the knife also. (no finger prints on any cards). rip the living shit up out of that card and throw those pieces of shit every  which way to your hearts content. pick up one piece of it and eat it. 

WHAT UP! that mother fucker can find tons of little pieces of the card be he aint going to find "THE CARD" and even if he has super fucking hands and assembles that shit like some kind of dickhead the last piece will be in my stomach 

apon further inspection i wrote the word genitally, it sounds better that way
Title: Re: A simple security puzzle.
Post by: Dickens018 on February 15, 2013, 08:19 pm
Nice try, but your selection is detected in 30 sec.   You are sentenced to a long, painful execution.


Title: Re: A simple security puzzle.
Post by: DotJPG on February 16, 2013, 04:17 am
FUCK. do i get any drugs before you kill me?
Title: Re: A simple security puzzle.
Post by: aredhel on February 18, 2013, 11:45 am
Put on the gloves, open the book, then open the deck of cards.
Put each card behind one of the pages. Note in your mind which card you are going to choose and remember the number of the page where it lies. Put the book in the safe, lock it, and write down the number on a piece of paper you are keeping on yourself.

This is probably wrong because I have not even used the tools provided, but my point is that any investigator can check which card is selected by searching through the remaining deck.


Title: Re: A simple security puzzle.
Post by: Delysid1064 on February 18, 2013, 05:14 pm
removing my answer because I want to see what others come up with ...
Title: Re: A simple security puzzle.
Post by: ihawttts on February 18, 2013, 05:42 pm
put on the gloves, take the cards out of the deck, choose on of them at random, and then fling all the cards so they fly everywhere around the room
Title: Re: A simple security puzzle.
Post by: ihawttts on February 18, 2013, 05:43 pm
Alternately, put on the gloves, take each card out of the deck, soak it in the water, then use the knife to peel the lettering off the cards, so each one becomes a blank card
Title: Re: A simple security puzzle.
Post by: dex on February 18, 2013, 07:19 pm
Hide the card in the deck of cards amirite
Title: Re: A simple security puzzle.
Post by: Baconmmm on February 18, 2013, 11:12 pm
50
Title: Re: A simple security puzzle.
Post by: Dickens018 on February 19, 2013, 01:37 am
You have chosen wisely, and live a long happy life.

This solution will not be accepted again
Title: Re: A simple security puzzle.
Post by: Dickens018 on February 19, 2013, 02:09 am
Dex has the right answer,  you must  hide your selected card in the deck,  and then randomly shuffle or  scatter the deck. 
Use the cloth to avoid leaving oil or fingerprints on cards.
You need to hid your choice so that it can't be determined by any attacker.
If  you remove the card and hide it in the safe, one only has to check the deck to see what is missing.   
Hide card and deck  in the safe,  and I either know the combination,  or get a safe cracker.

All the "tools" except cloth were just distractions. 
When you randomly hide the card in a random deck,  then you have security because attacker can only  guess your selection.
Our very asses depend on security and insuring we leave no clues like to open these doors and avoid obvious passwords.
BE SAFE.
Thanks for all the responses.

And for the one facing the long lingering execution, I'll be happy to provide drugs.  Will adrenalin be acceptable? 
Its kind of hard to have a really long lingering execution without it. 
What the hell, you are pardoned for being first
Title: Re: A simple security puzzle.
Post by: sayword on February 19, 2013, 02:18 am
nice 8)
Title: Re: A simple security puzzle.
Post by: kmfkewm on February 19, 2013, 02:55 am
This problem is kind of stupid because you don't specify any restrictions on the attacker. Can they just keep guessing cards until they have determined the correct one? If so, they will always win. Can they only guess once? If they can only guess once you could just select a card in your mind without even opening the deck, in which case the attacker has only a 1/52 chance of winning, so the odds are in your favor.
Title: Re: A simple security puzzle.
Post by: curiositymatrix on February 19, 2013, 03:04 am
I think you can do more with this puzzle - are you just saying the challenge is, "pick a card, and make it so no one can tell what it was?"

Why 60 minutes? I think the puzzle should be, with those tools, pick a card, and make it so someone CAN figure out which card it was, but make it take a long time. I'm working on a way to do that. Make some sort of puzzle with the book and the cards, like so:
Cards between the pages. You turn the page the face value of the card (jack is 11, queen 12, etc), turn forward for red suit, and back for black suit. The last card in this sequence is your card.

eh?
Title: Re: A simple security puzzle.
Post by: Dickens018 on February 19, 2013, 04:15 am
Yes, the challenge is indeed to simply "pick a card, and make it so no one can tell what it was."

You could select a card without opening the pack if you knew its was a standard deck, but it could be a deck of pictures. 
You could cut the deck and let that be your selection, but what if I have a way of telling where you cut the deck, like oil traces on the edge.  Shuffle the deck several times and you should cover your tracks. Secure crypto depends on hiding your very secret info in a sea of randomness. 
A system that lets you predict 1 bit out 8  with 60% accuracy will quickly be broken.
Yes, they could keep guessing,  but how do they know when correct.  If you had a password with only 52 options such as A1,  you are indeed screwed,  but that's because attacker can try each of 52 possible passwords,  and will see text with correct one. 
The only place to hide the card you select is in the randomness of the deck whether in one pack on the safe or tossed about the room.
The safe was included to imply there is safety where there is none. you just see what card is missing from deck.
Title: Re: A simple security puzzle.
Post by: DefaultUserID on February 19, 2013, 05:30 am
Scatter the gloves around the room, jam the knife into a wall, choose one card at random, eat the entire deck of cards, use water to wash them down, insert clean towel into empty water glass, read the book, lock book in safe, your secret will be safe!
Title: Re: A simple security puzzle.
Post by: etype on February 19, 2013, 05:34 am
haha^^^^
I like it. 
Title: Re: A simple security puzzle.
Post by: DefaultUserID on February 19, 2013, 06:41 am
haha^^^^
I like it.

See! you couldn't guess my card! HA
Title: Re: A simple security puzzle.
Post by: Dickens018 on February 19, 2013, 06:47 am
It does have the the dramatic flair,  but perhaps not good taste.  :)
Its certainly meets the requirement,  and uses all the props as a bonus
Title: Re: A simple security puzzle.
Post by: a10101 on February 19, 2013, 09:36 am
I see
Title: Re: A simple security puzzle.
Post by: Dickens018 on February 19, 2013, 03:19 pm
This puzzle had two points. First to show how easy it is to fall for false security,  like when users of The Farmers Market falsely thought using Hushmail  would protect them.
Second was to show how hard is it is to hide a secret like your password when its easy to determine friends, pets, DOB and
interests from Facebook. 
 
Title: Re: A simple security puzzle.
Post by: BalloonMan on February 20, 2013, 06:23 am
Knives are made of metal, meaning they will spark if scraped properly on the safe or the walls. Using the knife, shred a couple of pages of the book into the smallest pieces you can, until you have a baseball sized wad of fluffy paper fiber. Now use the knife to make a spark (either on the metal of the safe, a stone wall, or whatever). Next, use the rest of the book to fuel the fire, incinerating pack of cards. If possible, start the fire inside the safe and burn the gloves as well, locking the door to cause partial combustion of the rubber, filling the safe with toxic fumes. Next, smash the glass all over the floor, use the water to wet the towel. If it's feasible, stab the searcher with the knife and flee, otherwise keep the knife and sell it later. A good opportunity to stab the searcher is when he inhales the toxic fumes from the burnt gloves, using the wet towel to assist your own breathing.

Note that if you have a sunlit window, the glass can be used to start the fire by focusing the light onto the shredded pages. If you have access to any other combustible sources, feel free to burn them as well. If you stabbed and killed the searcher, feel free to burn the corpse. The searcher also probably has (had) some expensive equipment with which he plan(ned) to check for finger grease and so on. Take this equipment and sell it later.

Just to be a dick, you choose the card by assuming which cards will be in the deck. If it's a standard 52 card deck, there will be a 10 of hearts, or a 3 of clubs, or whatever. You don't even have to take a card from the pack.
Title: Re: A simple security puzzle.
Post by: teslaspigeon on February 20, 2013, 06:32 am
Scatter the gloves around the room, jam the knife into a wall, choose one card at random, eat the entire deck of cards, use water to wash them down, insert clean towel into empty water glass, read the book, lock book in safe, your secret will be safe!

I really like it but I doubt you could get all that done in the 5 minutes he gave us in the scenario.