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### Programming 9

Posted: Fri May 23, 2008 1:07 pm
I have tried to solve this challenge, and I don't know what I'm doing wrong. Perhaps I'm missing something, and that's why this one's difficulty is rated insane. Each of the steps sudoku solving (all solutions), hashing and blowfish decrypting (CBC) do not seem insanely difficult to me, but I never get the right solution. I assume that the solution must be something readable because the challenge says to "submit the most likely solution".

I've tested my decryption algorithm against the supplied encryption one, and it works.

Is there someone who's already solved this one that I can mail a solution to with all intermediate steps, so that he can tell me what I'm doing?

### Re: Programming 9

Posted: Sat May 24, 2008 8:05 am
I don't think this is an insane mission. It's quite easy.. (at least it was for me)
Send me a mail or pm with your solution and I will check it for you.
// Jimmy

### Re: Programming 9

Posted: Sat May 24, 2008 3:16 pm
Just finished it after HOURS of messing around with the blowfish cipher.. to find that the reason it wasn't giving me output was because I'd been passing the variable "cipherr" and having it decrypt "cipher".. Lesson learned: If you can't get your code to work.. Remember to check your bloody spelling!

Good luck man.

### Re: Programming 9

Posted: Fri May 30, 2008 3:42 am
How am I supposed to guess the microtime() based second half of the IV?

### Re: Programming 9

Posted: Sat May 31, 2008 1:55 pm
Does 128-bit Blowfish == Twofish? Or is there some subtle difference?

### Re: Programming 9

Posted: Sat Jun 14, 2008 12:26 pm
Finally finished off this mission, but it was enjoyable. If anyone's interested in the sudoku part, check out Exact Covers and Algorithm X on wikipedia. Kind of tricky to implement, but they will give you all solutions to the sudoku portion very quickly.

### Re: Programming 9

Posted: Sat Jun 14, 2008 12:30 pm
A small hint from my side, I used C# to complete this, but spent hours looking for a tiny Bug that seemingly spit out wrong solutions.
Nines9 (i guess, or someone else on IRC) suggested using the Algorithm that was mentioned in the Example Code - and that worked. It seems that certain implementations of Blowfish do not exactly work like the one used in this challenge.

### Re: Programming 9

Posted: Sun Sep 28, 2008 10:44 am
i need some help. I have done the sudoku part, and the SHA-1 hash, but i don't know how can i use the php file. maybe it is a dumb question but how can i run a php file? do i need some kind of interpreter or i have to use it from a html file directly??????? please help me because i don't know much about php and i'm stuck!

### Re: Programming 9

Posted: Sun Sep 28, 2008 1:48 pm
old_red_boots wrote:i need some help. I have done the sudoku part, and the SHA-1 hash, but i don't know how can i use the php file. maybe it is a dumb question but how can i run a php file? do i need some kind of interpreter or i have to use it from a html file directly??????? please help me because i don't know much about php and i'm stuck!

Look at the examples at the top of http://www.hackthissite.org/missions/pr ... wfish.phps

### Re: Programming 9

Posted: Tue Mar 17, 2009 10:00 pm
Um, it looks like this challenge may have changed. Perhaps in the past the challenge was to encrypt something, but now it is to decrypt it?

I can solve the suduku, get the sha1 hash, now I just need to put the encrypted text and the sha1 has I have together and decrypt, but the provided php code is just the encryption part! http://www.jmic.de/img/jm-blowfish.zip doesn't seem to include a "working" blowfish class that can decrypt either. Am I missing something?

I've tried using other blowfish programs none of them seem to handle my keys and cipher properly. And apparently CBC mode uses and IV, and with the provided code it comes from the time. How are we supposed to figure out what the IV was?

Is that part of the challenge? To implement our own CBC mode blowfish decrypter? Seems to be way to out there for me, I must be missing something.

Precisely, my questions are:
*To the people who have solved this one already, did you use an existing blowfish implementation or did you have to make your own?
*What am I supposed to do with the IV?