Feal is a block cipher designed by NTT. It is known to be insecure.
Feal is a block cipher designed by NTT in 1987. It is notable for being quite susceptible to a number of cryptographical attacks; it is interesting only for historical purposes.
Questions tagged [feal]
7 questions
5
votes
1 answer
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 then applied a Brut Force search in order to find…
Christine
- 363
- 2
- 5
3
votes
0 answers
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 problem is that I don't know what to do next as…
liam waters
- 31
- 1
2
votes
1 answer
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 the diagram below, the differential trail includes…
DingleBerry
- 23
- 2
2
votes
0 answers
Can a differential attack on FEAL4 yield multiple valid keys?
For my version of this attack I used the FEAL4 version depicted here http://theamazingking.com/crypto-feal.php and in the book "Applied Cryptanalysis Breaking Ciphers in the Real World -- Mark Stamp, Richard M. Low", which means that six 32-bit…
curious_cryptocopter
- 21
- 1
1
vote
0 answers
Differential Cryptanalysis of FEAL-4
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 of 0x80800000 which yields a differential of…
user1896168
- 19
- 1
1
vote
0 answers
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 will be 8 bytes firstly) I compute 8080 and after…
nmZ
- 75
- 5
-1
votes
1 answer
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 bits key; which is sliced to 32 bits. So on the…
nmZ
- 75
- 5