spatial ciphers/cryptanalysis techniques? - MathOverflow [closed] most recent 30 from http://mathoverflow.net 2013-05-19T21:00:14Z http://mathoverflow.net/feeds/question/37953 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/37953/spatial-ciphers-cryptanalysis-techniques spatial ciphers/cryptanalysis techniques? saran 2010-09-07T07:30:21Z 2010-09-08T01:17:14Z <p>Are there spatial ciphers/cryptanalysis techniques based on neighborhood spaces in a grid? More specially are there 5 orientation "spaces" with the values being north, south, east, west, neutral? </p> <p>I know this sounds more like rigorous math, but just need a simple explanation or some direction, as in resources or keywords or links (springerlink, arxiv, etc.)? </p> <p>Thanks for the help everyone.</p> <p>--</p> <p>(update)</p> <p>Well, in the context of the way I am handling the problem, I assigned these 5 values/symbols (N,S,E,W,I). Basically, I have globular shapes (whose descriptors don't matter) that are in a n x n grid of these "neighborhood spaces". They are not given - just a method I am tackling the problem with. I base these values (N,S,E,W,I) on whether these globules cross into neighboring spaces or are strictly inside a grid-cell. I treated globules extending/touching the grid lines shared between two neighboring cells as still crossing over into a neighboring space.</p> <p>Also, it may not use a cipher, but a code. So foremost, I am looking for ways to construct a cipher or a code based on spatial alignments. I hope this is clear, so let me know if clarifications are needed.</p> <p>Note: I - inside/ neutral.</p> http://mathoverflow.net/questions/37953/spatial-ciphers-cryptanalysis-techniques/37957#37957 Answer by saran for spatial ciphers/cryptanalysis techniques? saran 2010-09-07T07:46:42Z 2010-09-07T20:42:14Z <hr> http://mathoverflow.net/questions/37953/spatial-ciphers-cryptanalysis-techniques/37997#37997 Answer by saran for spatial ciphers/cryptanalysis techniques? saran 2010-09-07T19:08:55Z 2010-09-07T20:55:23Z <hr> http://mathoverflow.net/questions/37953/spatial-ciphers-cryptanalysis-techniques/38020#38020 Answer by sleepless in beantown for spatial ciphers/cryptanalysis techniques? sleepless in beantown 2010-09-08T00:53:10Z 2010-09-08T01:17:14Z <p>There is a classic substitution cipher technique that uses a 25-square ($5 \times 5$) grid which holds 25 of the 26 letters of the roman alphabet:</p> <pre><code>- + 1 2 3 4 5 - 1 A B C D E - 2 F G H I J - 3 K L M N O - 4 P Q R S T - 5 U V W X Y </code></pre> <p>It's effectively a short-hand technique for creating a <a href="http://en.wikipedia.org/wiki/Substitution_cipher" rel="nofollow"><strong>substitution cipher</strong></a> by viewing it as a toroidal lattice, letting <strong>NORTH</strong> define the mapping {'A'$\to$'U', 'B'$\to$'V', ... 'Y'$\to$'T'}, etc. Effectively, north maps the coordinates (x,y) to ($NORTH_x(x),NORTH_y(y)$), for $x,y \in$ {1,2,3,4,5}, </p> <blockquote> <p>$NORTH_x(t)=t$, for $1 \le t \le 5$</p> <p>$NORTH_y(t)=$ $t-1$ for $2\le t \le 5$, </p> <p>$NORTH_y(t)=5$ for $t=1$. </p> </blockquote> <p>Similar definitions exist for SOUTH, EAST, and WEST. The Identity direction or NULL direction stands for the identity function, $NULL(t)=t$.</p> <p>A message can be encoded with a single direction, meaning only one substitution cipher is used for the entire message. A message can be encoded with multiple directions, meaning that each sequential letter is encoded by a different direction, rolling over when you get to the end of the cipher.</p> <p>Napoleon used a variation of this, with two $5 \times 5$ grids, with a pass-phrase used for the second grid.</p> <p>This may have nothing to do with what you're asking for. Your explanation thus far is not illuminating enough for me to grasp what it is exactly that you are trying to do. Can you explain your ultimate end-goal? Is it to create an encrytion cipher? Is it to analyze an already existing encrypted message? Is it to analyze a particular encoding algorithm or technique?</p> <p>What exactly is the underlying problem which you are attempting to solve?</p>