Archive for heinäkuu, 2015

matasano Cryptochallenge (Part three)

Becoming more interesting.

80 Kggcafo(EK/{(dacm(i(xg}fl(gn(jikgf
82 Ieeacdm*GI-y*fcao*k*zedn*el*hkied
86 Maaeg`i.CM)}.bgek.o.~a{`j.ah.loma`
87 L``dfah/BL(|/cfdj/n/`zak/`i/mnl`a
88 Cooking MC's like a pound of bacon
90 Ammikle"OA%q"nkig"c"rmwlf"md"`caml

is resulty of our search, and key is definitely 88, but how to get there?

Somewhat sad string, contains apostrofe, and cant be fished with alnum() method of a stringe, even right string is wrong anyway.

Long story shortened, we have only 256 possible keys here, since keysize is one byte, because key is same long as chunks to encode. in our case, we have some chunks, we want to iterate from 1 to 256, xor all our chunks and see if result makes sence.

Quite good critery for such size would be some letter counting. In this case there were few unnecessary solution, which are easily seen due to compactness of output.

Lets count ‘a’s and if there is at least one ‘a present, than we gather this as possible candidate.

Here is challenge, and here is solution.

matasano Cryptochallenge (Part two)

Well, lets continue with finding xor


Again, we have strings encoded to hex, after decoding we get:

"KSSP"(longer string actually) 
"hit the bull's eye"

Second string is sane and xored with arbitrary bits of first string we get result:

"the kid don't play", which is same size like second input, since no control characters, sane symbols only)

Here is challenge, here is solution.

matasano Cryptochallenge (Part one)

There is such interesting, matasano cryptography challenge.


Lets do it, lets use for productivity Cloud.Math, nice cloud platform. You probably have to registrate there, but you will not regret it – fully fledged, very powerful mathsuite+python.. it cant get any better.


Anyway, here is solutiun to first part. And it is good to understand, that First we have string, which is represented by encoded hex bytes. each hex byte – corresponds to character. Coverting all hexes to string we get “I’m killing your brain like a poisonous mushroom

Afterward we take this string and encode it to base64, various ways to do it.


Also, i am back and will write mostly in english from now on, and mostly about cryptography or stuff i dig in university.