User talk:87.69.235.248

Your digaram of a Feistel cipher

I reverted your edit, because your diagram is wrong. Either you describe a cipher with n rounds. Then the round keys have indices from 0 to n-1. and the ciphertext blocks have indices n. In this case the text needs to be changed too. Or you describe a Feistel cipher with n+1 rounds. Then the round keys should have indices running from 0 through n and the ciphertext blocks have indices n+1. 81.62.73.125 (talk) 17:03, 12 September 2011 (UTC)[reply]

File:Feistel cipher diagram.png also have n+1 rounds + the text says:

i=0,1,\dots ,n

, which mean n+1 rounds. 87.69.235.248 (talk) 17:43, 12 September 2011 (UTC)[reply]

OK, let's try this with an example. Assume n=4. Hence there are 5 rounds, which have five round keys:

K_{0},K_{1},K_{2},K_{3},K_{4}

. The first round takes

L_{0},R_{0}

as input uses the key

K_{0}

and computes

L_{1},R_{1}

. The next round takes

L_{1},R_{1}

as input uses the key

K_{1}

and computes

L_{2},R_{2}

. Going further, the third round takes

L_{2},R_{2}

as input uses the key

K_{2}

and computes

L_{3},R_{3}

. You should see a pattern here: each round takes input

L_{i},R_{i}

as input uses the key

K_{i}

and computes Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "http://localhost:6011/en.wikipedia.org/v1/":): {\displaystyle L_{i+1]}, R_{i+1}} . I.e. the index of the result is always by 1 larger than the input and the index of the round key. I.e. for n=5, the last round key is

K_{4}

and the output is

L_{5},R_{5}

. More generally if the last round function is

K_{n}

then the result should be Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "http://localhost:6011/en.wikipedia.org/v1/":): {\displaystyle L_{n+1]}, R_{n+1}} and not

L_{n]},R_{n}

. Thus your diagram is incorrect. 81.62.73.125 (talk) 18:41, 12 September 2011 (UTC)[reply]

my file and File:Feistel cipher diagram.png are the same/ so you have two choices:

remove the PNG picture
change the text of the article

changing again to File:Feistel cipher diagram.png is stupid 19:00, 12 September 2011 (UTC)

This is the discussion page for an IP user, identified by the user's IP address. Many IP addresses change periodically, and are often shared by several users. If you are an IP user, you may create an account or log in to avoid future confusion with other IP users. Registering also hides your IP address.