Questions tagged [feal]

Feal is a block cipher designed by NTT. It is known to be insecure.

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Differential cryptanalysis of FEAL-4 recovering last subkeys

I am familiar with the differential cryptanalysis of small SPN-based ciphers like here: Tutorial of Amazing King with SPN (or mentioned in the book "The Block Cipher Companion" or the Tutorial of ...
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Linear cryptanalysis of FEAL-4

I am trying to find the sub keys of a FEAL-4 cipher. I am able to get a number of possibilities for $K_0$ after using Michael Stamps formula using a as a constant and going through $2^{32}$ keys. The ...
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126 views

Differential trails in FEAL-8

In this paper the authors describe a differential attack against FEAL-8. They find several short differential trails, then extend the attack to the full 8-Rounds of the cipher by algebraic means. In ...
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FEAL-4 Linear Cryptanalysis - Prevention

currently, I prepare for an exam about cryptanalysis. In class, we talked about linear cryptanalysis for FEAL-4. We constructed four linear equations, extended them to equations for three rounds and ...
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FEAL-4 Fk Function 4 Rounds

As I understood in FEAL-4 it needs 4 pair of round keys. Which means that we need to launch Fk function 4 times. My problem occurs starting the 2nd round. At the first round we have the original 64 ...
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FEAL-4 Wrong outputs of Round Functions

On page 2 of this article, there is example of FEAL-4. At round 2, the input to F (Round Function) is 0x80800000. As F accepts only 4 bytes I divide the input by 2 so that (As I assume the result ...
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Differential Cryptanalysis of FEAL-4 [duplicate]

I'm currently carrying out a differential attack on the FEAL-4 algorithm, however I have hit a bit of a wall. Basically I attacked the final round first ($K3$) using the differential characteristic ...