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Post Closed as "Needs details or clarity" by D.W., DrLecter, e-sushi, John Deters, Henrick Hellström
Tweeted twitter.com/#!/StackCrypto/status/550760108977045505
fix broken mathjax, misc. copyedits
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Ilmari Karonen
Ilmari Karonen
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i looked here:On page 46 of http://www.icg.isy.liu.se/courses/tsit03/forelasningar/cryptolecture04.pdfthese lecture notes on page 46. It, it seems to say that if we have a Feistel cipher, and plaintexts $(L_0, R_0)$ and $(L_{0}^{*}, R_))$$(L_0^*, R_0^*)$ with corresponding encryptions, then we can determine the key? But isn't this this not the case by Luby-Rackoff? I'm not entirely sure what the slideslides are even saying. They say that we can compute $R_3 \oplus R_{3}^{*}$$R_3 \oplus R_3^*$, but so what? How does this help determine the key?

i looked here: http://www.icg.isy.liu.se/courses/tsit03/forelasningar/cryptolecture04.pdf on page 46. It seems to say that if we have a Feistel cipher, and plaintexts $(L_0, R_0)$ and $(L_{0}^{*}, R_))$ with corresponding encryptions, then we can determine the key? But isn't this this not the case by Luby-Rackoff? I'm not entirely sure what the slide are even saying. They say that can compute $R_3 \oplus R_{3}^{*}$ but so what? How does this help determine the key?

On page 46 of these lecture notes, it seems to say that if we have a Feistel cipher, and plaintexts $(L_0, R_0)$ and $(L_0^*, R_0^*)$ with corresponding encryptions, then we can determine the key? But isn't this not the case by Luby-Rackoff? I'm not entirely sure what the slides are even saying. They say that we can compute $R_3 \oplus R_3^*$, but so what? How does this help determine the key?

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Wilson
Wilson
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Luby-Rackoff on Feistel ciphers

i looked here: http://www.icg.isy.liu.se/courses/tsit03/forelasningar/cryptolecture04.pdf on page 46. It seems to say that if we have a Feistel cipher, and plaintexts $(L_0, R_0)$ and $(L_{0}^{*}, R_))$ with corresponding encryptions, then we can determine the key? But isn't this this not the case by Luby-Rackoff? I'm not entirely sure what the slide are even saying. They say that can compute $R_3 \oplus R_{3}^{*}$ but so what? How does this help determine the key?