Re:GCHQ Code Cracking Challenge to recruit code breakers
by pbhjpbhj on Thursday December 01, 2011 @07:52AM
(#3299530)
The repititions have me curious.
Do you, or anyone, happen to know of a cypher-text analysis tool that will allow for example to quickly workout distributions of substrings, perform simply replacements and the like?
I guess I could code such a thing but my coding is pretty rusty.
---
Edit: I found these but question is still open if someone has a good tool to suggest.
Re:GCHQ Code Cracking Challenge to recruit code breakers
by sanswork on Thursday December 01, 2011 @06:54AM
(#3299367)
I remember them having a puzzle on their website about 11 years ago when I was still living in England, almost like a scavenger hunt with different smaller puzzles. The answer was an email address to send your CV. Unfortunately being Canadian I wasn't eligible.
Re:GCHQ Code Cracking Challenge to recruit code breakers
by gibybo on Thursday December 01, 2011 @07:57AM
(#3299550)
[Cryptic spoilers]
The first stage seems pretty luck based - you either recognize it pretty quickly as the type of code it is, or you're stuck there for days trying every interpretation you can think of. It doesn't help that a portion of the code is deceptively hidden :/
Left hand side:
Right hand side: There are lots of interesting features in this.I should add, cryptically, that there's more to the challenge, I believe, than simply meets the eye.
eb 04 af c2 bf a3 81 ec 0c fe c1 75 f9 31 c0 ba d0 c1 ca 08 8a 1c 0c 8a fe c1 75 e8 e9 5c 00 00 00 5c 58 3d 41 41 41 41 75 3b 5a 89 d1 89 e6 89 d1 89 df 29 cf 31 c0 31 8a 14 06 8a 34 1e 88 34 8a 1c 16 8a 17 30 da 88 d8 fe c0 cd 80 90 90 e8 00 01 00 00 31 c9 88 0c ef be ad de 02 04 0c 00 3c 04 88 1c 04 88 3c 0c 00 89 e3 81 c3 04 00 00 75 43 58 3d 42 42 42 42 df 29 cf f3 a4 89 de 89 db 31 d2 fe c0 02 1c 06 06 88 14 1e 00 f2 30 f6 17 47 49 75 de 31 db 89 9d ff ff ff 41 41 41 41
into either:
http://www.onlinedisassembler.com/
or
http://pyms86.appspot.com/desasm_hex
Do you, or anyone, happen to know of a cypher-text analysis tool that will allow for example to quickly workout distributions of substrings, perform simply replacements and the like?
I guess I could code such a thing but my coding is pretty rusty.
---
Edit: I found these but question is still open if someone has a good tool to suggest.
http://crypto.lkdev.com/fa.php http://www.richkni.co.uk/php/crypta/freq.php
http://git.aeminium.org/~slug/?p=programming/security.git;a=...
unsigned char image_com[] = { 0xeb, 0x04, 0xaf, 0xc2, 0xbf, 0xa3, 0x81, 0xec, 0x00, 0x01, 0x00, 0x00, 0x31, 0xc9, 0x88, 0x0c, 0x0c, 0xfe, 0xc1, 0x75, 0xf9, 0x31, 0xc0, 0xba, 0xef, 0xbe, 0xad, 0xde, 0x02, 0x04, 0x0c, 0x00, 0xd0, 0xc1, 0xca, 0x08, 0x8a, 0x1c, 0x0c, 0x8a, 0x3c, 0x04, 0x88, 0x1c, 0x04, 0x88, 0x3c, 0x0c, 0xfe, 0xc1, 0x75, 0xe8, 0xe9, 0x5c, 0x00, 0x00, 0x00, 0x89, 0xe3, 0x81, 0xc3, 0x04, 0x00, 0x00, 0x00, 0x5c, 0x58, 0x3d, 0x41, 0x41, 0x41, 0x41, 0x75, 0x43, 0x58, 0x3d, 0x42, 0x42, 0x42, 0x42, 0x75, 0x3b, 0x5a, 0x89, 0xd1, 0x89, 0x5c, 0x78, 0x24, 0x36, 0x89, 0xdf, 0x29, 0xcf, 0xf3, 0xa4, 0x89, 0xde, 0x89, 0xd1, 0x89, 0xdf, 0x29, 0xcf, 0x31, 0xc0, 0x31, 0xdb, 0x31, 0xd2, 0xfe, 0xc0, 0x02, 0x1c, 0x06, 0x8a, 0x14, 0x06, 0x8a, 0x34, 0x1e, 0x88, 0x34, 0x06, 0x88, 0x14, 0x1e, 0x00, 0xf2, 0x30, 0xf6, 0x8a, 0x1c, 0x16, 0x8a, 0x17, 0x30, 0xda, 0x88, 0x17, 0x47, 0x49, 0x75, 0xde, 0x31, 0xdb, 0x89, 0xd8, 0xfe, 0xc0, 0xcd, 0x80, 0x90, 0x90, 0xe8, 0x9d, 0xff, 0xff, 0xff, 0x41, 0x41, 0x41, 0x41, 0x42, 0x42, 0x42, 0x42, 0x32, 0x00, 0x00, 0x00, 0x91, 0xd8, 0xf1, 0x6d, 0x70, 0x20, 0x3a, 0xab, 0x67, 0x9a, 0x0b, 0xc4, 0x91, 0xfb, 0xc7, 0x66, 0x0f, 0xfc, 0xcd, 0xcc, 0xb4, 0x02, 0xfa, 0xd7, 0x77, 0xb4, 0x54, 0x38, 0xab, 0x1f, 0x0e, 0xe3, 0x8e, 0xd3, 0x0d, 0xeb, 0x99, 0xc3, 0x93, 0xfe, 0xd1, 0x2b, 0x1b, 0x11, 0xc6, 0x11, 0xef, 0xc8, 0xca, 0x2f }; unsigned int image_com_len = 221;
Usually, they've have a recruitment officer in the lobby of the TopCoder chat room. Very interesting competitions of varying skill levels.
The first stage seems pretty luck based - you either recognize it pretty quickly as the type of code it is, or you're stuck there for days trying every interpretation you can think of. It doesn't help that a portion of the code is deceptively hidden :/
"stage 2 of 3", however, looks quite fun :)
""" 0x00000010 d0c1ca08 j 0x32b0740 0x00000014 8a1c0c8a lwl t4,7306(s0) 0x00000018 fec175e8 swc2 $21,-15874(v1) 0x0000001c e95c0000 0x5ce9 0x00000020 005c583d 0x3d585c00 0x00000024 41414141 0x41414141 0x00000028 753b5a89 lwl k0,15221(t2) 0x0000002c d189e689 lwl a2,-30255(t7) 0x00000030 d189df29 slti ra,t6,-30255 0x00000034 cf31c031 andi zero,t6,0x31cf 0x00000038 8a14068a lwl a2,5258(s0) 0x0000003c 341e8834 ori t0,a0,0x1e34 0x00000040 8a1c168a lwl s6,7306(s0) 0x00000044 1730da88 lwl k0,12311(a2) 0x00000048 d8fec0cd lwc3 $0,-296(t6) 0x0000004c 809090e8 swc2 $16,-28544(a0) 0x00000050 00010000 sll zero,zero,0x4 0x00000054 31c9880c jal 0x22324c4 0x00000058 efbeadde ld t5,-16657(s5) 0x0000005c 02040c00 srl zero,t4,0x10 0x00000060 3c04881c 0x1c88043c 0x00000064 04883c0c jal 0xf22010 0x00000068 0089e381 lb v1,-30464(t7) 0x0000006c c3040000 sra zero,zero,0x13 0x00000070 7543583d 0x3d584375 0x00000074 42424242 c0 0x424242 0x00000078 df29cff3 scd t7,10719(s8) 0x0000007c a489de89 lwl s8,-30300(t6) 0x00000080 db31d2fe sd s2,12763(s6) 0x00000084 c0021c06 0x61c02c0 0x00000088 0688141e 0x1e148806 0x0000008c 00f230f6 sdc1 $f16,-3584(s1) 0x00000090 17474975 jalx 0x5251c5d 0x00000094 de31db89 lwl k1,12766(t6) 0x00000098 9dffffff sd ra,-99(ra) 0x0000009c 41414141 0x41414141 """