Jump to content

Talk:Unicity distance: Difference between revisions

Page contents not supported in other languages.
From Wikipedia, the free encyclopedia
Content deleted Content added
SineBot (talk | contribs)
m Signing comment by 143.111.80.33 - ""
Line 13: Line 13:
'''Another way to increase the unicity distance is to increase the number of possible valid sequences in the files as it is read. Since if for at least the first several blocks any bit pattern can effectively be part of a valid message then the unicity distance has not been reached. This is possible on long files when certain bijective string sorting permutations are used, such as the many variants of bijective BWT transforms.''' <span style="font-size: smaller;" class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/143.111.80.33|143.111.80.33]] ([[User talk:143.111.80.33|talk]]) 17:15, 11 March 2013 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
'''Another way to increase the unicity distance is to increase the number of possible valid sequences in the files as it is read. Since if for at least the first several blocks any bit pattern can effectively be part of a valid message then the unicity distance has not been reached. This is possible on long files when certain bijective string sorting permutations are used, such as the many variants of bijective BWT transforms.''' <span style="font-size: smaller;" class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/143.111.80.33|143.111.80.33]] ([[User talk:143.111.80.33|talk]]) 17:15, 11 March 2013 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->


== Broken character ==
== Broken character, questionable example ==


<blockquote>
<blockquote>
Line 20: Line 20:


The  is broken for me (Ubuntu, Firefox, with Japanese/Korean support). --[[User:Sydius|Sydius]] ([[User talk:Sydius|talk]]) 00:55, 19 August 2008 (UTC)
The  is broken for me (Ubuntu, Firefox, with Japanese/Korean support). --[[User:Sydius|Sydius]] ([[User talk:Sydius|talk]]) 00:55, 19 August 2008 (UTC)
:''Basically the bigger the unicity distance the better. For a one time pad of unlimited size, given the unbounded entropy of the key space, we have <math>U = \infty</math>, which is consistent with the [[one-time pad]] being theoretically unbreakable.''

:I improved the expression here, but the example is not really on target. I would not speak in terms of infinity, which will seem too theoretical even to the theoretically-minded, but rather point out that a one-time pad is used only once, for a message much shorter than the unicity length. A calculation with a ten-thousand word message in English would be great here. For this example: How long a key to get a unicity length of a million? How many key candidates with this key length (surely much greater than one)? It might not be enough for a conviction, but might still justify an arrest. [[Special:Contributions/178.38.151.183|178.38.151.183]] ([[User talk:178.38.151.183|talk]]) 17:33, 30 November 2014 (UTC)

Revision as of 17:33, 30 November 2014

WikiProject iconCryptography: Computer science Unassessed
WikiProject iconThis article is within the scope of WikiProject Cryptography, a collaborative effort to improve the coverage of Cryptography on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
???This article has not yet received a rating on Wikipedia's content assessment scale.
???This article has not yet received a rating on the importance scale.
Taskforce icon
This article is supported by WikiProject Computer science.

Meanings and abrevation of.. FER Ec/Io CAI Finger RFI

Please improve sentence structure

This paragraph gives me parsing problems, Should the second sentence be joined to the first as as it is read, since if? I cannot tell.

Another way to increase the unicity distance is to increase the number of possible valid sequences in the files as it is read. Since if for at least the first several blocks any bit pattern can effectively be part of a valid message then the unicity distance has not been reached. This is possible on long files when certain bijective string sorting permutations are used, such as the many variants of bijective BWT transforms. — Preceding unsigned comment added by 143.111.80.33 (talk) 17:15, 11 March 2013 (UTC)[reply]

Broken character, questionable example

Basically the bigger the unicity distance the better. For a one time pad, given the unbounded entropy of the key space, we have U = , which is consistent with the one-time pad being theoretically unbreakable.

The  is broken for me (Ubuntu, Firefox, with Japanese/Korean support). --Sydius (talk) 00:55, 19 August 2008 (UTC)[reply]

Basically the bigger the unicity distance the better. For a one time pad of unlimited size, given the unbounded entropy of the key space, we have , which is consistent with the one-time pad being theoretically unbreakable.
I improved the expression here, but the example is not really on target. I would not speak in terms of infinity, which will seem too theoretical even to the theoretically-minded, but rather point out that a one-time pad is used only once, for a message much shorter than the unicity length. A calculation with a ten-thousand word message in English would be great here. For this example: How long a key to get a unicity length of a million? How many key candidates with this key length (surely much greater than one)? It might not be enough for a conviction, but might still justify an arrest. 178.38.151.183 (talk) 17:33, 30 November 2014 (UTC)[reply]