Talk:XXTEA

message: Reference post: http://groups.google.com/group/sci.crypt/browse_thread/thread/5ed40f85e693ef04
Further investigation needs to be done with respect to the viability of this algorithms security.
-Anon.  —Preceding unsigned comment added by 78.46.82.176 (talk) 18:45, 17 December 2008 (UTC)
thread_title:  Collisions 

message: From the article: "the algorithm was presented in an unpublished technical report in October 1998 (Wheeler and Needham, 1998)."
By "unpublished" do the editors mean an "unpublished work" in the copyright law sense of "author has not distributed copies of the work to the public", or only in the sense of "this article was first published outside of scholarly journals"? --Damian Yerrick (talk | stalk) 03:04, 4 October 2007 (UTC)
thread_title:  What do you mean by unpublished? 

message: If I use the code provided in the article, without modification, in my own programs, what license would it be covered under? GFDL seems to be a strange license to release source code under. Is the code in the public domain, or covered by some other license like the GPL? Algebra 00:10, 11 October 2007 (UTC)
replies: text: As far as I can tell, a derivative of PD code is also PD if the changes by themselves do not make an original work. --Damian Yerrick (talk | stalk) 22:27, 11 October 2007 (UTC)

text: Using this code without modification is a bad idea. It contains obvious bugs. Haael (talk) 09:19, 4 July 2010 (UTC)
thread_title:  Legal implications of using the provided code verbatim 

message: If anyone can provide a reference to a cryptologic research paper explaining this simple phenomenon, please do. If not, please write one. Currently I only have a working C source code of a program that quickly finds partial state collisions for 3 full cycles of XXTEA or for 6 full cycles of an XXTEA-like cipher with 16-bit words with a total time*memory complexity naturally equal to 248. It's a simple demonstration of this natural quality of all such incomplete UFN constructions that are meant to support arbitrarily large blocks. A change in any given number of words cannot cover the entire unbounded block after any fixed number of cycles, therefore partial state collisions will always occur. For XXTEA, it is as complex as finding a collision between two 6-word (192-bit) random numbers, iterating the cipher through which the change will be canceled out on every cycle leaving the rest of the block unaffected. This 296 search is easily accellerated by a time-memory trade-off. My guess is that once found, such partial collisions can assist in key recovery with a simple algebraic or guess-and-determine attack. So personally, I would advise to use 8 full cycles for 128-bit security. Ruptor 23:35, 30 October 2007 (UTC)
replies: text: Ruptor, Wikipedia is not the place for original research. Please provide a reference to formal cryptanalysis or remove the vulnerability paragraph. cdv (talk) 00:54, 11 April 2008 (UTC)
replies: text: CDV, I know what Wikipedia is and what it isn't. It is certainly a place where people come to find knowledge. If I can't stick your nose into a reference to some old book where trivial TMTO algorithms for finding collisions are explained, it doesn't mean that this obvious property should not be pointed out. A working program for finding those collisions is no research. There is nothing to research. It's an obvious property that must be pointed out. But it is certainly NOT a vulnerability and there is no research proving that it is exploitable or not. This property is there whether there is an official "peer reviewed" academic publication describing it or not and removing that paragraph would be equivalent to disinformation. I have pointed it out in one of my papers published at the SASC-2008, but it is such a trivial thing that it is hardly worth writing a paper about. Ruptor (talk) 02:38, 12 April 2008 (UTC)
replies: text:  The "original research" policy is that, unless a fact has been noted in a published work, then it's not appropriate to include it in Wikipedia. — Matt Crypto 08:32, 12 April 2008 (UTC)
replies: text:  Then consider it noted in a published work. Ruptor (talk) 16:11, 17 April 2008 (UTC)
replies: text:  Which work, so that others can look it up? --Damian Yerrick (talk | stalk) 16:51, 17 April 2008 (UTC)
replies: text:  EnRUPT: First all-in-one symmetric cryptographic primitive. The SASC 2008 workshop record PDF.zip, page 268. Ruptor (talk) 22:50, 18 April 2008 (UTC)
thread_title:  Partial Ciphertext Collisions 

message: The image in the summary does not look accurate, Xr-1 and Xr+1 need to be switched. According to the specification y, which holds the data for the next block, is shifted by 2 and 3; and z, holding the data from the previous block, as being shifted by 5 and 4. The specification also has z XOR the sub-key and y XOR the delta multiple, the image shows the opposite to all these.  — Preceding unsigned comment added by Informalmunch (talk • contribs) 23:06, 22 January 2015 (UTC)
replies: text: Are you still active on Wikipedia? Since you're the author of the original image :File:Algorithm diagram for XXTEA cipher.png, it seems that Informalmunch is correct. -- intgr [talk] 09:40, 23 January 2015 (UTC)
thread_title:  Round diagram image wrong?