67 replies to this topic

[dawh]

I know the real-life problem is often solved with brute-attacks, no argument for me there. This however is a small scale model - 51/3=17 - at most 16 guessing rounds.

I still would have liked to "patch" it up a little. I would have been much happier designing something that does not suggest a brute-force attack is feasible e.g. the algorithm in the first game. As I said, I was too anxious to start the game

I haven't made much progress cracking your algorithm, but I do think I have a workable one of my own. Not sure if I would want to host it next since I'm not usually around much on Thursday evenings (or at all). I still have to encode everything and take another look at it, but I think it holds to octopuppy's guidelines and it's fairly easy to calculate in your head, so long as you know what it is.

[Cherry Lane]

I haven't made much progress cracking your algorithm, but I do think I have a workable one of my own. Not sure if I would want to host it next since I'm not usually around much on Thursday evenings (or at all). I still have to encode everything and take another look at it, but I think it holds to octopuppy's guidelines and it's fairly easy to calculate in your head, so long as you know what it is.

I, too, have come up with one (still testing it). Will someone please solve araver's so we can move on? I'm completely stumped.

[araver]

OK, then

Spoiler for here's a hint

Each unknown depends on only one letter in the command.

It is a question similar to those of the algorithm in Game 2.

[dawh]

OK, then

Spoiler for here's a hint

Each unknown depends on only one letter in the command.

It is a question similar to those of the algorithm in Game 2.

I've been staring at the lists of commands (spending more time than I probably ought ) and I still don't see anything that sets the binary condition for the second letter or what separates the values for the eighth character either.

The lists both look pretty random to my eyes. It seems like the difference between OHIO and IOWA might provide the best chance at cracking it, but I don't see what one has that the other lacks (they are in separate lists in both cases).

[araver]

I've been staring at the lists of commands (spending more time than I probably ought ) and I still don't see anything that sets the binary condition for the second letter or what separates the values for the eighth character either.

The lists both look pretty random to my eyes. It seems like the difference between OHIO and IOWA might provide the best chance at cracking it, but I don't see what one has that the other lacks (they are in separate lists in both cases).

OK, that's exactly the problem with such an IF THEN 1 ELSE 0 rule, it kinda looks random for a small number of cases unless you stumble on a pattern.

Spoiler for Hint

It's arguable that it may have appeared less random in the algorithm in game 2 because the rule was applied several times independently and then re-combined.

I was able to see something by sorting the list on a fixed letter and then observe if there seems to be a rule in the output(passwords). E.g. in game 2 if you sort after the fourth letter (alphabetically) then the second letter of the password suddenly exhibits a pattern - it's odd (in hex) up to a point, then it becomes even.

Regarding starting a new Crack the Code game: I'm up for it, regardless of the solution for this algorithm (We can leave it be for now and think between games or I can provide the solution in "spoilers")

So who wants to start it?

[Cherry Lane]

I've been staring at the lists of commands (spending more time than I probably ought ) and I still don't see anything that sets the binary condition for the second letter or what separates the values for the eighth character either.

The lists both look pretty random to my eyes. It seems like the difference between OHIO and IOWA might provide the best chance at cracking it, but I don't see what one has that the other lacks (they are in separate lists in both cases).

I've not made any progress, either, but I'd disagree that OHIO and IOWA provide any special clue, since the hint we were given stated that

Spoiler for each condition

is based on a single letter of the command

Meanwhile, I'm rewriting my own proposed code. On trial some passwords were requiring a full 40 seconds to develop.

[octopuppy]

OK, I think I have it now...

Spoiler for it

The 3rd letter is the last prime-numbered letter in the command
Unknown 1 is true when the second to last letter <J ( or maybe <=J )
Unknown 2 is true when the last prime-numbered letter >J ( or maybe >=J )

Is that right?
With hindsight I feel like I should have spotted these sooner but somehow they seem to have eluded all of us.
I was beginning to wonder if it all hinged on whether the sum of all the ASCII characters was a prime number, or something like that

[araver]

OK, I think I have it now...

Spoiler for it

The 3rd letter is the last prime-numbered letter in the command
Unknown 1 is true when the second to last letter <J ( or maybe <=J )
Unknown 2 is true when the last prime-numbered letter >J ( or maybe >=J )

Is that right?
With hindsight I feel like I should have spotted these sooner but somehow they seem to have eluded all of us.
I was beginning to wonder if it all hinged on whether the sum of all the ASCII characters was a prime number, or something like that

to all three answers. The algorithm is now completely discovered.

<J was the rule in fact for both of my booleans (one of the booleans is in fact the opposite of yours). I can count to 10 using my fingers so I considered the first 10 letters of the alphabet to be friendlier(A..I)

Edited by araver, 28 October 2010 - 08:59 PM.

[octopuppy]

to all three answers. The algorithm is now completely discovered.

<J was the rule in fact for both of my booleans (one of the booleans is in fact the opposite of yours). I can count to 10 using my fingers so I considered the first 10 letters of the alphabet to be friendlier(A..I)

I must say that those unknowns have proved to be a very tricky part of your hash, and considering that they could be evaluated very quickly, that's something you'd have to consider a great success (except that the code could be cracked without knowing them, lol). Seriously though, there are bits of that hash that would be time consuming, like counting the letters or vowels, but the quickest parts were the hardest to break. Interesting... I can't wait for the next one!

[Cherry Lane]

Hooray for octopuppy! Showing you are the true Evil Mastermind.

Here's a question resulting from my attempted code development: What's the requirement for having to remember all the steps in the code? You've established that since you cant see the password characters after you've entered them, the remaining letters shouldn't depend too much on what was already entered (for those of us with short memories). But in this hash, there may be an implementation problem in remembering which rules to apply to which characters of the password (eg, does the munber of vowels become the third character or the fourth?).

Octopuppy's original code had some elegance that later ones have lacked: That the same basic rules are applied throughout the construction of the password. Code #2 mixed that up a bit, but at least repeated the same requirements for the first 4 characters and the last 4. Code #3 has essentially 8 independent requirements. The one I've been trying to construct does also, but I've found when trying to apply it I have to look back at my cheat sheet to know what to do next, which is not in keeping with the spirit of the game.

Thoughts?