# Tag Info

6

Before we start with vectorial Boolean functions, let's recall the definition of the nonlinearity of a Boolean function: $$\mathcal{NL}(f) = \min_{a \in \mathbb{F}_2^n} d_H(f, \ell_a \oplus b),$$ where $\ell_a \oplus b$ represents the affine Boolean function defined by the bitvector $a$: $\ell_a(x) = a \cdot x$ ($\cdot$ is the dot product). The above ...

3

This '.' is not 'AND' operation , its modular multiplication in the Galois Field $$GF(2^8)$$ and other operation $$\oplus$$ used in Mix Column Step of AES encrytion is modular addition in the Galois Field $$GF(2^8)$$. Here is a link to youtube channel by Christoff Paar where you can understand well, Watch lecture 7 and 8. Hope it helps.

2

I understand that AES would be a better choice for applications where all the data is available at once, permitting the use of large blocks. RC4 on the other hand is more suited for applications where continuous data (that may not be available all at once) is to be encrypted (e.g., real-time data). No, this is not accurate. The block size of AES is just ...

1

AES S-box DDT is not uniform but it has a higher resistant to differential attacks than DES because of maximum probablity of input output pair of differential is 4/256.

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The answer "GCM is a good option as it combines encryption and integrity in one mechanism. " is a bit misleading. GCM uses one after another: 1-st encryption in counter mode and then GHASH to authenticate the data. In the recent intel processors CLMUL-NI is used to speed up the GHASH operations. Benefits of GCM over CBC+HMAC: is much faster, as the ...

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