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CHATX - a thread starter that's not as easy as it looks.

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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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#50057 — CHATX - a thread starter that's not as easy as it looks.

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

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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#50058

On Monday, 20 September 2021 at 10:18:00 UTC+1, 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 

Staring at this, it looks like it may be only shuffling, but
with x’s added as maybe separators of some sort?

Hmmm. Where have I seen a crappy shuffle algorithm recently?

M
— 

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#50060

On 20/09/2021 15:00, MM wrote:
> On Monday, 20 September 2021 at 10:18:00 UTC+1, 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
> 
> Staring at this, it looks like it may be only shuffling, but
> with x’s added as maybe separators of some sort?

A good start. I will not confirm or deny except to say that the x's are 
indeed added - but not as separators as such.

> Hmmm. Where have I seen a crappy shuffle algorithm recently?

Oh, mine should be even easier to break than that. I think it's 
breakable by eye alone, no computer power needed.

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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#50061

On Monday, 20 September 2021 at 15:17:22 UTC+1, Richard Heathfield wrote:
> On 20/09/2021 15:00, MM wrote: 
> > Staring at this, it looks like it may be only shuffling, but 
> > with x’s added as maybe separators of some sort?
> A good start. I will not confirm or deny except to say that the x's are 
> indeed added - but not as separators as such.
> > Hmmm. Where have I seen a crappy shuffle algorithm recently?
> Oh, mine should be even easier to break than that. I think it's 
> breakable by eye alone, no computer power needed.

Tantalising! If I assume all the x's are nulls, and delete them, then
the last group of letters on each of lines 3 and 4 suggest "encrypto".

I think my approach is too brutal. My brain hurts!

M 
--

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#50062

On 20/09/2021 18:52, MM wrote:
> On Monday, 20 September 2021 at 15:17:22 UTC+1, Richard Heathfield wrote:
>> On 20/09/2021 15:00, MM wrote:
>>> Staring at this, it looks like it may be only shuffling, but
>>> with x’s added as maybe separators of some sort?
>> A good start. I will not confirm or deny except to say that the x's are
>> indeed added - but not as separators as such.
>>> Hmmm. Where have I seen a crappy shuffle algorithm recently?
>> Oh, mine should be even easier to break than that. I think it's
>> breakable by eye alone, no computer power needed.
> 
> Tantalising!

Good! :-)

One small hint to save you some pain...

> If I assume all the x's are nulls, and delete them, then
> the last group of letters on each of lines 3 and 4 suggest "encrypto".

You are right that the x's must be removed, but I think removing them at 
the beginning would be a stupendously bad idea. They do have a purpose.

You are also correct that the word "encrypt" appears in the original.

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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#50063

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

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#50064

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!

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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#50065

On 20.09.21 20:42, Richard Heathfield wrote:
> 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!
> 

That was fun. Thank you for this great idea. :-)

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#50068

On 20/09/2021 19:50, Max wrote:
> On 20.09.21 20:42, Richard Heathfield wrote:
>> 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!
>>
> 
> That was fun. Thank you for this great idea. :-)


SPOILER: Read no further if you want to finish on your own.
SPOILER: Read no further if you want to finish on your own
SPOILER: Read no further if you want to finish on your ow
SPOILER: Read no further if you want to finish on your o
SPOILER: Read no further if you want to finish on your
SPOILER: Read no further if you want to finish on your
SPOILER: Read no further if you want to finish on you
SPOILER: Read no further if you want to finish on yo
SPOILER: Read no further if you want to finish on y
SPOILER: Read no further if you want to finish on
SPOILER: Read no further if you want to finish on
SPOILER: Read no further if you want to finish o
SPOILER: Read no further if you want to finish
SPOILER: Read no further if you want to finish
SPOILER: Read no further if you want to finis
SPOILER: Read no further if you want to fini
SPOILER: Read no further if you want to fin
SPOILER: Read no further if you want to fi
SPOILER: Read no further if you want to f
SPOILER: Read no further if you want to
SPOILER: Read no further if you want to
SPOILER: Read no further if you want t
SPOILER: Read no further if you want
SPOILER: Read no further if you want
SPOILER: Read no further if you wan
SPOILER: Read no further if you wa
SPOILER: Read no further if you w
SPOILER: Read no further if you
SPOILER: Read no further if you
SPOILER: Read no further if yo
SPOILER: Read no further if y
SPOILER: Read no further if
SPOILER: Read no further if
SPOILER: Read no further i
SPOILER: Read no further
SPOILER: Read no further
SPOILER: Read no furthe
SPOILER: Read no furth
SPOILER: Read no furt
SPOILER: Read no fur
SPOILER: Read no fu
SPOILER: Read no f
SPOILER: Read no
SPOILER: Read no
SPOILER: Read n
SPOILER: Read
SPOILER: Read
SPOILER: Rea
SPOILER: Re
SPOILER: R
SPOILER:
SPOILER:
SPOILER
SPOILE
SPOIL
SPOI
SPO
SP
S



Encryption:

Read a PAIR of lines from input. If one is shorter, pad it with 'x's. If 
the lines are an odd number of characters long, add an 'x' to each.

You now have your input:

ABCDEFGHIJKL
MNOPQRSTUVWx

Think of it as squares of 2x2 characters:

AB CD EF GH IJ KL
MN OP QR ST UV Wx

Rotate each square 90 deg clockwise:

MA OC QE SG UI WK
NB PD RF TH VJ xL

That's the whole thing.

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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#50069

On 20.09.21 22:02, Richard Heathfield wrote:
> On 20/09/2021 19:50, Max wrote:
>> On 20.09.21 20:42, Richard Heathfield wrote:
>>> 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!
>>>
>>
>> That was fun. Thank you for this great idea. :-)
> 
> 
> SPOILER: Read no further if you want to finish on your own.

Hey, Richard, no need for spoilers, is there? You took some time to make 
this and there are still people working on it. If you don't mind, I 
would prepare the next cipher, but I won't be able to do so before the 
weekend.

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#50070

On 20/09/2021 21:24, Max wrote:
> On 20.09.21 22:02, Richard Heathfield wrote:
>> On 20/09/2021 19:50, Max wrote:
>>> On 20.09.21 20:42, Richard Heathfield wrote:
>>>> 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!
>>>>
>>>
>>> That was fun. Thank you for this great idea. :-)
>>
>>
>> SPOILER: Read no further if you want to finish on your own.
> 
> Hey, Richard, no need for spoilers, is there?

I thought I should post an explanation whilst it's still clear in my 
head, not least because it's been cracked. Anyone who wants to finish 
the puzzle, as it were, need only not scroll down past the spoiler warning.

> I 
> would prepare the next cipher, but I won't be able to do so before the 
> weekend.

That's the ticket! I think it does this group no harm to post ciphers 
from time to time, to give cryptanalysts something to practise on.

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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#50066

Op 20-9-2021 om 20:42 schreef Richard Heathfield:
> 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
> 
> 

Good for you, Max! I'm working on it, but it may take a while ..

> Ladies and gentlemen, we have a winner!
> 



Ozz

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#50067

On 20.09.21 21:43, wizzofozz wrote:
> Op 20-9-2021 om 20:42 schreef Richard Heathfield:
>> 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
>>
>>
> 
> Good for you, Max! I'm working on it, but it may take a while ..

Serendipity. Have fun! :-)


> 
>> Ladies and gentlemen, we have a winner!
>>
> 
> 
> 
> Ozz

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#50073

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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#50075

On 21/09/2021 15:00, Phil Carmody wrote:
> Nicely done both!

And a fine blow-by-blow account of your analysis.

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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#50078

On 21.09.21 16:00, Phil Carmody wrote:
> Richard Heathfield <rjh@cpax.org.uk> writes:
> 


[...]

> 
> 
> This is how I approached it - very low-tech, perhaps a bit too manual.

Very nice explanation of your approach. I think doing it low-tech gets 
the most fun out of puzzles like this.

Yet, tbh, I started with a frequency analysis, just to know, what I was 
up against. It looked very English.

Next, I took Richard's advice to heart, to eyeball this. And the first 
thing to look for in English texts are the "th"s, amIright? So I 
realized, there were no "th"s across, but 4 down. Especially the 3 at 
the left stood out, so I looked around and stumbled across the matching 
"e ", "is" and "at" in the neighborhood. From there I kept going and 
when I was sure that it made sense, I Excelled (rather Gnumericed) the 
rest out of the ciphertext. Too bad, I can't post this here. Great idea 
of you to do all of this in bash/Perl so you can share your work here.

So, to make my answer just that extra bit harder to crack, I used extra 
spaces to split up the "th"s and made lines of equal length.

> 
> 
> 

[...]

> 
> So each block of 4 has been rotated clockwise to encrypt.

Argh! Of course! I didn't see that.

> 
> Nicely done both!

That was indeed a nice puzzle. Not just "crack by numbers", but also not 
too hard to get frustrated. Great job, Richard.

> 
> Phil
> 

Max

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#50079

On 21/09/2021 22:31, Max wrote:

<snip>

> 
> Argh! Of course! I didn't see that.

"That" being the entire encryption algorithm. So it would appear that
you had no idea how the encryption actually worked. (Extra credit to
Phil for spotting that.) Yet you were still the first who was able to
encode a message in such a way that my decrypter worked on it.

I hope Austin is reading, because this is typical Eve thinking. Max
didn't have any idea of the workings of the algorithm, but he still came
up with a speedy crack *and* was able to mimic the encryption process
without knowing the underlying logic in that process.

Austin, you can't assume that Eve will play by your rules. Eves are
tricksy buggerses, and they have all manner of nasssty things in their
pocketses. Never take Eve for granted.

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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#50080

On 22.09.21 00:03, Richard Heathfield wrote:
> On 21/09/2021 22:31, Max wrote:
> 
> <snip>
> 
>>
>> Argh! Of course! I didn't see that.
> 
> "That" being the entire encryption algorithm. So it would appear that
> you had no idea how the encryption actually worked.

No. But I found a different algorithm (the zigzag-pattern) that led to 
the same result.

> (Extra credit to
> Phil for spotting that.) Yet you were still the first who was able to
> encode a message in such a way that my decrypter worked on it.
> 
> I hope Austin is reading, because this is typical Eve thinking. Max
> didn't have any idea of the workings of the algorithm, but he still came
> up with a speedy crack *and* was able to mimic the encryption process
> without knowing the underlying logic in that process.
> 
> Austin, you can't assume that Eve will play by your rules. Eves are
> tricksy buggerses, and they have all manner of nasssty things in their
> pocketses. Never take Eve for granted.
> 

Well said.

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#50115

Op 21-9-2021 om 16:00 schreef Phil Carmody:
> 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.

I could not ignore "two" after a while, which was a bit annoying. I also 
kept seeing "recon" and "approximation", somehow.
The frequency count did immediately say "transposition".
The strange thing is, that I pretty early saw that encrypt was spelled 
over two lines, but I did not seriously follow up on it. Later this was 
key of course.

> 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
>

I like this seperation. When I figured out how it worked I guess I shot 
myself in the foot by keeping all text.


> 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.

When I finally came to implementing the encryption I figured I needed to 
make every line length a multiple of 4. This is probably related.
I like the perl onelines, but I always find perl a bit hard to read.
My solutions also have the mod 2 = 1/0 , but that's probably logical.

In my other post I encrypted base64 encodings of my python solutions.
Here are my versions (finalized late at night so a bit messy as usual):

decrypt:
#!/usr/bin/python

import sys

x=open(sys.argv[1]).readlines()

def m(a,b):
     if len(a) != len(b):
         print "bad"
     la = len(a)
     if la%2==0:
         a+=" "
         b+=" "
         la += 1
     i=1
     pt=""
     while i < la*2:
         pt += (a[i%la] + b[i%la])
         i += 2
     return pt

for l in range(len(x)/2):
     print m(x[l*2].rstrip('\n'),x[2*l+1].rstrip('\n'))



encrypt:
#!/usr/bin/python
import sys

x=open(sys.argv[1]).readlines()

for l in x:
     pt = l.rstrip('\n')
     lpt = len(pt)
     if lpt % 4 != 0:
         pt += "x"*(4-lpt%4)
         lpt = len(pt)
     b=[pt[lpt/2+j]+pt[j] for j in range(lpt/2)]
     print "".join([b[i] for i in range(len(b)) if i % 2 == 0])
     print "".join([b[i] for i in range(len(b)) if i % 2 == 1])


Ozz

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#50144

wizzofozz <oxxxxxxxxxxxs@gmail.com> writes:
> When I finally came to implementing the encryption I figured I needed
> to make every line length a multiple of 4. This is probably related.
> I like the perl onelines, but I always find perl a bit hard to read.
> My solutions also have the mod 2 = 1/0 , but that's probably logical.
>
> In my other post I encrypted base64 encodings of my python solutions.
> Here are my versions (finalized late at night so a bit messy as usual):
>
> decrypt:
> #!/usr/bin/python
>
> import sys
>
> x=open(sys.argv[1]).readlines()
>
> def m(a,b):
>     if len(a) != len(b):
>         print "bad"
>     la = len(a)
>     if la%2==0:
>         a+=" "
>         b+=" "
>         la += 1
>     i=1
>     pt=""
>     while i < la*2:
>         pt += (a[i%la] + b[i%la])
>         i += 2
>     return pt
>
> for l in range(len(x)/2):
>     print m(x[l*2].rstrip('\n'),x[2*l+1].rstrip('\n'))
>
>
>
> encrypt:
> #!/usr/bin/python
> import sys
>
> x=open(sys.argv[1]).readlines()
>
> for l in x:
>     pt = l.rstrip('\n')
>     lpt = len(pt)
>     if lpt % 4 != 0:
>         pt += "x"*(4-lpt%4)
>         lpt = len(pt)
>     b=[pt[lpt/2+j]+pt[j] for j in range(lpt/2)]
>     print "".join([b[i] for i in range(len(b)) if i % 2 == 0])
>     print "".join([b[i] for i in range(len(b)) if i % 2 == 1])


Assuming I've got the line ending/length protocols correct:

--- 8< ---- encoder -----
#!/usr/bin/perl -w
use strict;
use warnings;
my ($it,$ib);
while(defined($it=<>) and defined($ib=<>)) {
    chomp($it); chomp($ib);
    my ($lt,$lb)=(length($it),length($ib));
    if($lt&1) { $it.=' '; $lt++; }
    if($lb&1) { $ib.=' '; $lb++; }
    if($lt<$lb) { $it.='x'x($lb-$lt); $lt=$lb; }
    if($lt>$lb) { $ib.='x'x($lt-$lb); $lb=$lt; }
    for my $o (0..1) {
        for(my $i=0; $i<$lt; $i+=2) {
            print(substr($ib,$i+$o,1),substr($it,$i+$o,1));
        }
        print("\n");
    }
}
--- 8< ---- encoder test -----
echo "For those of you still on
lockdown, can you identify
the algorithm used to encrypt
this text?
For extra credit, cut some code
that can approximate a decryption
-- harder than it looks, as I can
attest.
And don't say nothing
ever happens here." | perl r4.pl
lFcrdtwo,econ you itelt fn
ook ohns  af you sdinlioy 
ttie aegtrxtxmxuxex xoxexcxyxt
hhs tlxo?ixhx xsxdxtx xnxrxpx 
tFar eat apcrexim,tc t semr poienx
hot cxnra prodita eua doceyctdo  x
a-t sa.dxrxtxax xtxlxoxsx xsxIxcxn
t-ehtr ex xhxnxix xoxkx,xax x xax 
eAed danptns yenetxixg
vnr hop'e sah ro.hxnx 
--- 8< ---- encoder test end -----

--- 8< ---- decoder -----
#!/usr/bin/perl -w
use strict;
use warnings;
my ($it,$ib);
while(defined($it=<>) and defined($ib=<>)) {
    chomp($it); chomp($ib);
    my ($lt,$lb)=(length($it),length($ib));
    die("lengths not equal: '$it'=$lt '$ib'=$lb")if($lt!=$lb);
    die("lengths not even: '$it'=$lt '$ib'=$lb")if($lt&1);
    my @o=('','');
    for my $o (0..1) {
        for(my $i=0; $i<$lt; $i+=2) {
            $o[$o^1].=substr($it,$i+$o,1).substr($ib,$i+$o,1);
        }
        $o[0]=~s/ ?x+$//; $o[1]=~s/ ?x+$//;
    }
    print("$o[0]\n$o[1]\n");
}
--- 8< ---- decoder test -----
echo "lFcrdtwo,econ you itelt fn
ook ohns  af you sdinlioy
ttie aegtrxtxmxuxex xoxexcxyxt
hhs tlxo?ixhx xsxdxtx xnxrxpx
tFar eat apcrexim,tc t semr poienx
hot cxnra prodita eua doceyctdo  x
a-t sa.dxrxtxax xtxlxoxsx xsxIxcxn
t-ehtr ex xhxnxix xoxkx,xax x xax
eAed danptns yenetxixg
vnr hop'e sah ro.hxnx " | perl r4d.pl
For those of you still on
lockdown, can you identify
the algorithm used to encrypt
this text?
For extra credit, cut some code
that can approximate a decryption
-- harder than it looks, as I can
attest.
And don't say nothing
ever happens here.
--- 8< ---- decoder test end -----

Note, the decoder uses my encoder output as its input, not Richard's
original.

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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