Re: Please test this encryption

From: Richard Heathfield (dontmail_at_address.co.uk.invalid)
Date: 08/20/03 

Date: Wed, 20 Aug 2003 06:11:10 +0000 (UTC)

LinuxGuy wrote:

> Translation: You thought it was some silly monoalphabetic scheme,

Correction: I thought that this was a possibility. And it was a possibility.
It still is a possibility, if your plaintext is random gibberish. But if
the plaintext is English, the overwhelming likelihood is that this is not a
monoalphabetic.

> tried to crack it and it did not work........Funny you just could not
> come out and say "I tried to crack it but could not"....

Look, pal, this is getting tedious. You haven't cracked my algorithm, even
though I've published it on my site, so why the hell should I crack yours,
which you are clearly afraid to publish?

If you can crack the following ciphertext, all by yourself, without any
input from the sci.crypt regulars, maybe I'll start taking you seriously.

The algorithm, and a complete reference implementation in C, can be found at
http://users.powernet.co.uk/eton/crypto/cdx2.html - vanilla s-boxes were
used (see sb.c). The plaintext is ordinary English text, which contains the
phrase "the kudos of knowing" just before the halfway mark. The key is also
ordinary English text. In this case, the key is a rather long 62 bytes, so
I'll give you some of it here:

O?O?W?a?T?e?c?e?o?s?c?W?S?i?p?d?h?n?i?s?W?S?r?g?l?d?o?e?r?p?

There you are - half the key! Here's the ciphertext.

8D 75 A2 B7 14 58 58 B8 CF C1 E3 99 00 3C EC 54 | .u...XX......<.T
93 E9 2F BB 20 9E 4E 22 E2 14 E9 62 26 20 61 A8 | ../. .N"...b& a.
DB D0 2C 1A AF 2A BA 93 9D 46 63 3C 0F 54 5D 84 | ..,..*...Fc<.T].
05 98 07 70 60 59 71 B0 B0 96 5B 1F 44 5B 6D B7 | ...p`Yq...[.D[m.
EB B3 50 29 A9 61 6B ED 03 0D F6 EC EE 88 2B 3C | ..P).ak.......+<
52 4E 95 DB 05 64 7A 44 02 16 EF 16 DB 0F 1A 68 | RN...dzD.......h
D0 D3 55 8B F4 B1 77 03 AE 2A 27 88 59 37 DA 40 | ..U...w..*'.Y7.@
28 3C DD 9C C4 99 2B 36 90 7E 68 96 47 80 01 00 | (<....+6.~h.G...
C2 A6 D3 9F 60 F5 4C D5 9F 3D B9 CE AF 4B AF 51 | ....`.L..=...K.Q
F4 B6 81 C2 EF 5D 87 BB 7F F2 D4 10 D2 4A E7 D1 | .....].......J..
99 AF C9 CF D8 77 3C 14 2A B8 CA E8 C9 22 DB 31 | .....w<.*....".1
54 37 02 4B 72 7D 65 F6 E0 E2 E3 A2 45 31 4E 21 | T7.Kr}e.....E1N!
D7 96 77 18 95 48 49 44 66 6F 80 F6 30 BF 83 D8 | ..w..HIDfo..0...
4B A6 BF 9B 28 FC C3 B8 35 E5 6C 2E BD EF A1 17 | K...(...5.l.....
8B 9E 5F 03 9E E5 AE A9 EE 0B FC 9A B3 29 03 CD | .._..........)..
F6 29 84 CC 23 B0 F2 27 4D 2F 64 40 5E 96 EC C3 | .)..#..'M/d@^...
DA 33 09 72 3B D3 39 0D DC 33 D3 8F 2C CA 1E 93 | .3.r;.9..3..,...
19 F8 98 6D F9 D5 64 92 34 87 B5 67 20 A8 3E 7D | ...m..d.4..g .>}
56 FA 5B B7 77 93 AA 46 28 54 00 17 93 8A 44 99 | V.[.w..F(T....D.
A6 0F 96 A9 BD E4 32 BE B3 1E EB 4E 43 1D A2 D0 | ......2....NC...
D2 77 B5 B5 50 34 8A 3C AC 19 21 4F 15 3F 3F 69 | .w..P4.<..!O.??i
B5 2A 3B E5 B5 C4 FE A7 CB 7B 6A 7E E7 EC E1 6C | .*;......{j~...l
F3 68 A8 B5 ED F4 D9 88 93 C6 F0 CB 5B A8 9C 97 | .h..........[...
F3 96 9F 18 C9 25 BF 6B 76 E1 3C D7 CE 19 A7 8B | .....%.kv.<.....
90 8F C9 76 E5 E2 93 F9 D2 4A FF 72 51 24 97 8D | ...v.....J.rQ$..
D0 61 A7 51 69 14 39 43 29 28 90 AD C1 11 CD A2 | .a.Qi.9C)(......
B9 AF 84 BB 6B 2E 3E EE A7 2D AA B8 F1 CE D1 8A | ....k.>..-......
03 0A F1 27 31 0C EC EA 2B 18 73 1D A3 38 F2 0D | ...'1...+.s..8..
C5 3D 43 75 5A 3A E8 00 45 32 A1 39 2C 5B E9 EB | .=CuZ:..E2.9,[..
00 BA 97 D5 F1 82 5E 75 FE ED C9 A5 9B 3D 97 D5 | ......^u.....=..
48 1C | H.

I have given you far more information about my algorithm (i.e. ALL of the
available information) than you have given me about yours.

You have already said that you have a degree in mathematics, and many years
experience of cryptography. I don't have any kind of a degree at all, and
no serious experience in cryptography. So you should find it trivial to
break my cipher, given that I've supplied you with not just the ciphertext,
but the algorithm, a reference implementation, hints on the plaintext,
hints on the key, and even half the key itself.

If you can't crack this, why should we bother trying to deduce the algorithm
that you are too scared to show us? 

-- 
Richard Heathfield : binary@eton.powernet.co.uk
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R answers, C books, etc: http://users.powernet.co.uk/eton

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