For Robin

[Sanjøy]

http://www.canyoucrackit.co.uk/

[Scotty C]

is that SFW

[robin]

It's x86 machine code, almost certainly a routine to execute on either FreeBSD or Linux.

I'll decypher it further when I have a moment:

00000000 <data>:
0: eb 04 jmp 6 <data+0x6>
2: af scas %es:(%edi),%eax
3: c2 bf a3 ret $0xa3bf
6: 81 ec 00 01 00 00 sub $0x100,%esp
c: 31 c9 xor %ecx,%ecx
e: 88 0c 0c mov %cl,(%esp,%ecx,1)
11: fe c1 inc %cl
13: 75 f9 jne e <data+0xe>
15: 31 c0 xor %eax,%eax
17: ba ef be ad de mov $0xdeadbeef,%edx
1c: 02 04 0c add (%esp,%ecx,1),%al
1f: 00 d0 add %dl,%al
21: c1 ca 08 ror $0x8,%edx
24: 8a 1c 0c mov (%esp,%ecx,1),%bl
27: 8a 3c 04 mov (%esp,%eax,1),%bh
2a: 88 1c 04 mov %bl,(%esp,%eax,1)
2d: 88 3c 0c mov %bh,(%esp,%ecx,1)
30: fe c1 inc %cl
32: 75 e8 jne 1c <data+0x1c>
34: e9 5c 00 00 00 jmp 95 <data+0x95>
39: 89 e3 mov %esp,%ebx
3b: 81 c3 04 00 00 00 add $0x4,%ebx
41: 5c pop %esp
42: 58 pop %eax
43: 3d 41 41 41 41 cmp $0x41414141,%eax
48: 75 43 jne 8d <data+0x8d>
4a: 58 pop %eax
4b: 3d 42 42 42 42 cmp $0x42424242,%eax
50: 75 3b jne 8d <data+0x8d>
52: 5a pop %edx
53: 89 d1 mov %edx,%ecx
55: 89 e6 mov %esp,%esi
57: 89 df mov %ebx,%edi
59: 29 cf sub %ecx,%edi
5b: f3 a4 rep movsb %ds:(%esi),%es:(%edi)
5d: 89 de mov %ebx,%esi
5f: 89 d1 mov %edx,%ecx
61: 89 df mov %ebx,%edi
63: 29 cf sub %ecx,%edi
65: 31 c0 xor %eax,%eax
67: 31 db xor %ebx,%ebx
69: 31 d2 xor %edx,%edx
6b: fe c0 inc %al
6d: 02 1c 06 add (%esi,%eax,1),%bl
70: 8a 14 06 mov (%esi,%eax,1),%dl
73: 8a 34 1e mov (%esi,%ebx,1),%dh
76: 88 34 06 mov %dh,(%esi,%eax,1)
79: 88 14 1e mov %dl,(%esi,%ebx,1)
7c: 00 f2 add %dh,%dl
7e: 30 f6 xor %dh,%dh
80: 8a 1c 16 mov (%esi,%edx,1),%bl
83: 8a 17 mov (%edi),%dl
85: 30 da xor %bl,%dl
87: 88 17 mov %dl,(%edi)
89: 47 inc %edi
8a: 49 dec %ecx
8b: 75 de jne 6b <data+0x6b>
8d: 31 db xor %ebx,%ebx
8f: 89 d8 mov %ebx,%eax
91: fe c0 inc %al
93: cd 80 int $0x80
95: 90 nop
96: 90 nop
97: e8 9d ff ff ff call 39 <data+0x39>
9c: ff 41 41 incl 0x41(%ecx)
9f: 41 inc %ecx
a0: 41 inc %ecx

Cheers,
Robin

[scottishselise]

What are they asking for? You to enter the next in code in sequence?

[robin]

No, just a code word. If you analyze the program (or decide that the x86 op codes are a red herring and do some other analysis on the numbers) then you will discover a code word. You enter the code word in the box and if you're right you proceed to the next stage.

Cheers,
Robin

[neil]

Well that wasn't too difficult
http://www.canyoucrackit.co.uk/soyoudidit.asp

[robin]

Well that wasn't too difficult
http://www.canyoucrackit.co.uk/soyoudidit.asp

Did you work it out and if so did you work it out as per my disassembly above, or is that a red herring?

Cheers,
Robin

[kerryxeg]

I think it's an underhand way of identifying possible hackers! Well done Neil!

[ed]

I think Neil is just good at googling!

[robin]

We're still trying to crack it here - it's a cypher system of some sort - but then what else would you expect It might, however, be a wind up ... I did try 42 as the answer

[robin]

It's a symmetrical cypher - in other words if A cyphers to B the B cypers to A ...

[neil]

Well that wasn't too difficult
http://www.canyoucrackit.co.uk/soyoudidit.asp

Did you work it out and if so did you work it out as per my disassembly above, or is that a red herring?

Cheers,
Robin

I should probably come clean. I did spend a bit of time today looking at it, playing with matrices, and in the end getting nowhere. Your disassembly just left me confused so in the end i had to go fot the link i found on Seloc If you manage to crack it I'll be impressed!

[neil]

Well that wasn't too difficult
http://www.canyoucrackit.co.uk/soyoudidit.asp

Did you work it out and if so did you work it out as per my disassembly above, or is that a red herring?

Cheers,
Robin

I should probably come clean. I did spend a bit of time today looking at it, playing with matrices etc, and in the end getting nowhere. Your disassembly just left me confused so in the end i had to go for the link i found on Seloc If you manage to crack it I'll be impressed!

[robin]

Well I've cracked the code in the sense that I have a working implementation of the cypher, so I can cypher arbitrary input to output, but I cannot work out what the actual thing to cypher is. In other words, I can make X->Y and I imagine Y will be the keyword, but I cannot find the X to start with.

Judging by the HTML of the page the keyword might be 16 characters long exactly, or certainly no longer than 16 characters.

The cypher is 1:1, in other words it doesn't lengthen or shorten the plain text when cyphering it.

So I'm looking for a string of between 1 and 16 bytes than when (de)cyphered produces the keyword. I know the keyword must be text 'cos you type it on a keyboard. This reduces the number of starting bytes to around 60 (26 lower case, 26 upper case and a couple of sensible punctuation marks).

My next gambit is to brute decrypt the 160 byte block of bytes starting at each byte (in other words 160 times) and see if anything pops out. Then maybe start looking at columns in the data.

For now I'm off to bed though ...

[colintinto]

It's not a wind up, it's some government agency looking for people to apply for a job as a code breaker.

Saw some news article on it.