Execution Style

[wrtlprnft]

I loved the part where you ended up with a hackvm program… And I instantly recognized it as such

[osterlaus]

Yeah, this was a really nice challenge! Loved to handle this different ways of simplification

[megabreit]

Same here... 3 months ago I didn't even know about hackvm and today I got the result faster than I was able to find out the real meaning of the C99 syntax error.

And thanks for not taking this to the extremes like in "Compression"

[Chocoholic]

Totally agree with megabreit. This was a fun challenge, but it could have been made more challenging, for example by including code in some obscure esoteric programming language, like l33t or piet.

[DaymItzJack]

Totally agree with megabreit. This was a fun challenge, but it could have been made more challenging, for example by including code in some obscure esoteric programming language, like l33t or piet.

I'm glad he didn't. ;p

I solved most of it by using http://codepad.org, seeing as I don't have a Perl interpreter with me. I couldn't figure out the C language so I just converted it to python.

[jonik555]

I didnt know what to do with that error in C program compiling, so I rewrited it to Python.

[arthur]

i love it, too

[chephy]

How did you extract the data from the image?

For me, convert (from imagemagick) and the BSD »file« command made the challenge very easy…

[aurora]

this was a very nice challenge, even though the "executable" confused me a lot ... till i found the 7z string in it . i used a small php script to extract the "executable" btw.:

Code: Select all

#!/usr/bin/env php
<?php

$dat = file_get_contents(__DIR__ . '/Doll2.png');
if (preg_match('/IDAT(.*?)IEND/s', $dat, $match)) {
	file_put_contents(__DIR__ . '/Doll2.bin', gzinflate(substr($match[1], 2, -4)));
}

[Hippo]

I spent most time on the first step. I have written pixels & 0xff to the file and nothing appeared.
I am still confused why conversion to BMP gives other result (of course ordered from bottom to top).

On line compilers/interpretters helped a lot.

Funny one.

[yes-man]

I really loved this one. Didn't take that long, but was great fun.

Suppose I skipped the executable step, just extracted the 7z directly, without the executable wrapper. Was that intended or just luck? ^^
About the first step, yes, it was about recognizing that some binary data is encoded in the picture ... but it was kind of obvious.