# Tag Info

Accepted

### Linear Approximation Table of S-Box for SPN

In Howard Heys' tutorial, the S-box $S$ maps 4 bits to 4 bits. It is defined by the following lookup table: ...

### Why is AES not a Feistel cipher?

The simple answer is "Because its an SPN cipher". What is difference between Feistel and SPN? SPN operates on whole data in one round, where as Feistel divides data into N parts where N>=2 , then ...
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### What is the diffrence between Feistel networks and SPN?

In a Feistel networks (from the German IBM cryptographer Horst Feistel), the input is divided into two blocks ($L_0$ and $R_0$) which interact with each other. Main example is DES. basic construction:...

### modified substitution permutation networks

Your construction is completely insecure: a single known plaintext / ciphertext block pair is sufficient to decrypt all blocks encrypted with the same key. Specifically, let me write your block ...
Accepted

### Substitution-permutation network visualizer

You might be interested in TikZ for Cryptographers: PGF/TikZ is a tandem of languages for producing vector graphics from a geometric/algebraic description. PGF is a lower-level language, while TikZ ...
Accepted

### modified substitution permutation networks

So, the mixing of the $n$ keys is at most as secure as having a uniformly distributed single key. If your key randomness is not strong, doing this kind of mixing can make the key distribution nearer ...

### DES/AES invertibility

DES is a Feistel cipher where the round function doesn't need to be invertible. Therefore, when designing a Feistel cipher you will have invertible and non-invertible S-box options. In contrast, AES ...