Ciao a tutti gringhelli :)

excuse me for my terrible english o:p

First of all turn on the stereo with your favorite cds to turn on your
brain :)

I'm listening:

Helloween - I can
Nofx - Champs elisče
PornoRiviste - Dove Vai
PornoRiviste - Anima
Punkreas - La canzone del bosco
Punkreas - Il mercato del niente
Shandon - Questo si chiama Ska
Lag Wagon - Know It All
Marilyn Manson - Sweet Dreams
No Doubt - Don't Speak

mmmmhhh... stop my crazy introduction !!!!

Let's speak about the pusillus' crackme:
I've think this:

I've created a system of equations using the conditions that i've found
in the disassembled program, then:

[(a xor b)xor(c xor d)]xor[(e xor f)xor(g xor h)]xor a = 71
[(a xor b)xor(c xor d)]xor[(e xor f)xor(g xor h)]xor b = 18
[(a xor b)xor(c xor d)]xor[(e xor f)xor(g xor h)]xor c = 59

ecc. ecc.....

Then, the XOR have the associative and commutative properties:

(a xor b) xor c = a xor (b xor c)
a xor b = b xor a

And....... :)

a xor a = 0
x xor 0 = x

so i obtain:

b xor c xor d xor e xor f xor g xor h = 71
a xor c xor d xor e xor f xor g xor h = 18
a xor b xor d xor e xor f xor g xor h = 59

ecc. ecc...

I haven't touched the first equation e i've XORed it with the others
and simplifying all i've finally obtained:

b xor c xor d xor e xor f xor g xor h = 71
a xor b = 71 xor 18 ==> b = 71 xor 18 xor a
a xor c = 71 xor 59 ==> c = 71 xor 59 xor a
.......

Substituting the b,c,d,e,f,g,h in the first equation i've found: A=68
and using A, i can found all the other variables....

xoring the solutions with 32 and translating them to decimal, i found
the ascizz code of the serial. ;)


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aLoNg3x --- along3x.cjb.net

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