Tag Info

Accepted

Understanding the wide trail design strategy

Given the importance of the wide-trail strategy in modern symmetric-key cryptography, this question really deserves an answer (and a much better score). Since nobody else has tried, I'll give a brief ...
• 1,876
Accepted

How 2 rounds in AES achieve full diffusion?

AES diffusion is taking cared of by 3 main functions: SubBytes Shift Rows Mix Columns SubBytes works as a 8-bit S-box. Thus if one bit change, the 8 bits of the byte are likely to change. With this ...
• 10k

How does AES introduce confusion and diffusion?

Put simply: The add key layer ensures the encryption function is only computable by someone who knows the key Adds some confusion because the key is (psuedo) random The subBytes s-box layer creates ...
• 19.8k
Accepted

Confusion and Diffusion in the AES functions

I should start by saying that the notions confusion and diffusion can not provide an in-depth understanding of the design of the AES, simply because they are not specific enough. Instead, the key to ...
• 1,876

Which sub operation is more expensive in the AES encryption process?

The table lookup implementations usually combine the SubBytes and ShiftRows steps with the MixColumns step. Different implementations/hardware/etc make general statements impossible, but this paper ...
• 1,463
Accepted

Prove the branch of number of Advanced Encryption Standard

The dear user @kodlu has answered to the similar question with excellent discussion but I want to answer with linear algebra argument. We have two definitions for MDS (Maximum Distance Separable) ...
• 204
Accepted

• 19.8k

Why is confusion and diffusion never talked about in asymmetric crypto?

The topic is a little dated, but similar concepts are discussed using slightly different language. People have questioned whether the computation of individual bits of discrete logarithms, or RSA ...
• 25.4k

ECB... lacks diffusion(?)

I agree with your observation. The wiki's assessment of the weakness of ECB being a lack of diffusion is not very precise. I have a feeling that they're using diffusion in a generic sense, not the ...
• 376
Accepted

does OFB mode has diffusion on the plaintext?

if we will change one bit in the plaintext, more than one bit will be changed in the ciphertext? In Output Feedback Mode, no, it does not. Specifically, if you change one bit of the plaintext and ...
• 150k
Accepted

What's the difference between confusion/diffusion and mode of operation?

AES is a mode of operation, and confusion/diffusion are what we use to achieve a certain mode. AES is a block cipher, which replaces one fixed-length block of bits (plaintext) with another fixed-...
• 19.8k
Accepted

Application of MDS matrices in serial and round-based implementations

what types of MDS matrices can be applied to serial or round-based implementations or both of them? Serial matrices utilise a trade-off to reduce hardware requirement while incurring additional ...
• 2,268
Accepted

What are “weak” and “strong” output-input bit dependencies?

There can be various measures of bit dependency. A classical measure would be how close the process is to achieving what Claude Shannon termed diffusion, which is sometimes termed the strict avalanche ...
• 25.4k