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| From | Phil Carmody <pc+usenet@asdf.org> |
|---|---|
| Newsgroups | sci.crypt |
| Subject | Re: CHATX - a thread starter that's not as easy as it looks. |
| Date | 2021-09-21 17:00 +0300 |
| Organization | A noiseless patient Spider |
| Message-ID | <87czp2do4k.fsf@zotaspaz.fatphil.org> (permalink) |
| References | <si9jk4$188$1@dont-email.me> <siakbv$j80$1@gioia.aioe.org> <siakmd$ilv$1@dont-email.me> |
Richard Heathfield <rjh@cpax.org.uk> writes: OK, I'm too slow, so at least I can have a stab... tTealkt lo hh nistfer tbaaen ersirx Original and winning solution left as spoiler space. This is how I approached it - very low-tech, perhaps a bit too manual. > On 20/09/2021 19:36, Max wrote: >> On 20.09.21 11:17, Richard Heathfield wrote: >>> lFcrdtwo,econ you itelt nx >>> ook ohns af you sdinliofy >>> ttie aegtrxtxmxuxex xoxexcxyt >>> hhs tlxo?ixhx xsxdxtx xnxrxpx >>> tFar eat apcrexim,tc t semr poexx >>> hot cxnra prodita eua doceyctdion >>> a-t sa.dxrxtxax xtxlxoxsx xsxIxcn >>> t-ehtrxex xhxnxix xoxkx,xax x xax >>> eAed danptns yenetxig >>> vnr hop'e sah ro.hxnx >>> >> >> >> >> eI nhvtr siie aiyhhrn ui >> teae. Nacd cnptei,gbltk >> ht stteo. aey' olf lno >> tie' hos eLst sta loullw >> ook hhssglmc.dCwe!r han >> fcr ttii aoek ohne sTMaxx > > > Ladies and gentlemen, we have a winner! 1st, 5th and 7th lines have capital letters in the 2nd column => pairs of characters may have been swapped (at least in odd lines) "algorithm", "encrypt", "decryption" half-readable, and missing letters appear to be on the next line => odd and even lines come in pairs. So, first stab: $ echo "lFcrdtwo,econ you itelt nx ook ohns af you sdinliofy ttie aegtrxtxmxuxex xoxexcxyt hhs tlxo?ixhx xsxdxtx xnxrxpx tFar eat apcrexim,tc t semr poexx hot cxnra prodita eua doceyctdion a-t sa.dxrxtxax xtxlxoxsx xsxIxcn t-ehtrxex xhxnxix xoxkx,xax x xax eAed danptns yenetxig vnr hop'e sah ro.hxnx " | perl -pe 's/(.)(.)/$2$1/g if($.&1)' Flrctdowe,oc noy utile txn ook ohns af you sdinliofy tteia gerttxmxuxex xoxexcxyxt hhs tlxo?ixhx xsxdxtx xnxrxpx Ftrae taa cperix,mctt s me ropxex hot cxnra prodita eua doceyctdion -a tasd.rxtxax xtxlxoxsx xsxIxcxn t-ehtrxex xhxnxix xoxkx,xax x xax Aeded natpsny neteixg vnr hop'e sah ro.hxnx Zigzag pattern shows the words more clearly now => keep that idea, isolate the black squares from the white ones White: [...] | perl -pe 's/(.)(.)/$2 /g if($.&1);s/(.)(.)/ $2/g if($.%2==0)' F r t o e o o t l x o h s f y u s i l o y t e a g r t m u e o e c y t h l o i h s d t n r px F r e t a c e i , c t s m o x x o x r r d t u o e c d on - a d r t a t l o s s I c n - h r e h n i o k , a ax A d d n t s y n t i g n o ' a o h nx For those of you still oxy the algorithm used to encrypt For extra credit, cut some codxox -- harder than it looks, as I can And don't say nothing => This is good, keep it, although note that the line endings are broken in places, due to dumb (ie. no) handling of odd-length lines in the script. I'll just overlook such stray characters for now Black: [...] | perl -pe 's/(.)(.)/ $1/g if($.&1);s/(.)(.)/$1 /g if($.%2==0)' l c d w , c n y u i e t n o k o n a o d n i f t i e t x x x x x x x x xt h s t x ? x x x x x x x x x x t a a p r x m t e r p ex h t c n a p o i a e a d c y t i n a t s . x x x x x x x x x x x xn t e t x x x x x x x x x x x x x x e e a p n e e xg v r h p e s h r . x x => Ooops, however, words are vaguely visible, reverse the swapping l c d w , c n y u i e t n o k o n a o d n i f t i e t x x x x x x x x x t h s t x ? x x x x x x x x xx t a a p r x m t e r p e x h t c n a p o i a e a d c y t in a t s . x x x x x x x x x x x x n t e t x x x x x x x x x x x x xx e e a p n e e x g v r h p e s h r . xx lockdown, can you identinf this text?xxxxxxxxxxxxxxxxxxt that can approximate a decrypteix attest.xxxxxxxxxxxxxxxxxxxxxxxxxn ever happens here.xxg => apart from the line endings, we've got English again. Let's interleave the two halves back together: For those of you still oxy lockdown, can you identinf this text?xxxxxxxxxxxxxxxxxxt the algorithm used to encrypt For extra credit, cut some codxox that can approximate a decrypteix -- harder than it looks, as I can attest.xxxxxxxxxxxxxxxxxxxxxxxxxn And don't say nothing ever happens here.xxg => Errors in line endings mostly cancel out and can be fixed up/ignored by eye. But we're left with the question of what transformation has really been done. So let's analyse this algorithm on a simpler cyphertext, knowing as we do that 2x2 blocks are important as it's pairs of characters and pairs of lines that are relevant: Black: echo "12abWX 34cdYZ" | perl -pe 's/(.)(.)/$2 /g if($.&1);s/(.)(.)/ $2/g if($.%2==0)' 2 b X 4 d Z = 24bdXZ White: echo "12abWX 34cdYZ" | perl -pe 's/(.)(.)/$1 /g if($.&1);s/(.)(.)/ $1/g if($.%2==0)' 1 a W 3 c Y = 13acWY Interleaved: 24bdXZ 13acWY So each block of 4 has been rotated clockwise to encrypt. Nicely done both! Phil -- We are no longer hunters and nomads. No longer awed and frightened, as we have gained some understanding of the world in which we live. As such, we can cast aside childish remnants from the dawn of our civilization. -- NotSanguine on SoylentNews, after Eugen Weber in /The Western Tradition/
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CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-20 10:17 +0100
Re: CHATX - a thread starter that's not as easy as it looks. MM <mrvmurray@gmail.com> - 2021-09-20 07:00 -0700
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-20 15:17 +0100
Re: CHATX - a thread starter that's not as easy as it looks. MM <mrvmurray@gmail.com> - 2021-09-20 10:52 -0700
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-20 19:10 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Max <maxturv26@gmx.net> - 2021-09-20 20:36 +0200
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-20 19:42 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Max <maxturv26@gmx.net> - 2021-09-20 20:50 +0200
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-20 21:02 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Max <maxturv26@gmx.net> - 2021-09-20 22:24 +0200
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-20 22:08 +0100
Re: CHATX - a thread starter that's not as easy as it looks. wizzofozz <oxxxxxxxxxxxs@gmail.com> - 2021-09-20 21:43 +0200
Re: CHATX - a thread starter that's not as easy as it looks. Max <maxturv26@gmx.net> - 2021-09-20 21:50 +0200
Re: CHATX - a thread starter that's not as easy as it looks. Phil Carmody <pc+usenet@asdf.org> - 2021-09-21 17:00 +0300
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-21 15:22 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Max <maxturv26@gmx.net> - 2021-09-21 23:31 +0200
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-21 23:03 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Max <maxturv26@gmx.net> - 2021-09-22 00:22 +0200
Re: CHATX - a thread starter that's not as easy as it looks. wizzofozz <oxxxxxxxxxxxs@gmail.com> - 2021-09-25 13:29 +0200
Re: CHATX - a thread starter that's not as easy as it looks. Phil Carmody <pc+usenet@asdf.org> - 2021-09-26 14:39 +0300
Re: CHATX - a thread starter that's not as easy as it looks. Richard Harnden <richard.nospam@gmail.com> - 2021-09-21 15:07 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-21 15:18 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Phil Carmody <pc+usenet@asdf.org> - 2021-09-21 21:43 +0300
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-21 20:41 +0100
Re: CHATX - a thread starter that's not as easy as it looks. wizzofozz <oxxxxxxxxxxxs@gmail.com> - 2021-09-25 02:24 +0200
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-25 05:24 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Richard Harnden <richard.nospam@gmail.com> - 2021-09-25 13:56 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-25 14:21 +0100
Re: CHATX - a thread starter that's not as easy as it looks. Richard Heathfield <rjh@cpax.org.uk> - 2021-09-25 14:28 +0100
Re: CHATX - a thread starter that's not as easy as it looks. wizzofozz <oxxxxxxxxxxxs@gmail.com> - 2021-09-25 16:11 +0200
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