All Questions
7 questions
0
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What is the need of substitution and permutation networks in AES?
I have tried to answer this question for quite some time now. But a complete intuitive understanding still eludes me.
Consider an alternate construction for a block cipher without any substitution and ...
- 69
2
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0
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69
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ε-close to t-wise inependence of SPN (AES)
According to theorem 3.13, the 6 rounds of AES is 0.472-close to pairwise independence. It is also mentioned t-wise independence used to analyze higher order derivates attacks. it is also mentioned 3-...
- 2,278
0
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1
answer
164
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Can we design a block cipher based on SP-network without loss of E/D similarity theoretically?
I understand what SP-network (Substitution-Permutation Network) and Feistel Network look like. And those ciphers based on Feistel (e.g. DES) often achieve so called E/D similarity, which indicates ...
- 165
2
votes
1
answer
1k
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DES/AES invertibility
My professor has posted a couple of practice questions that so far I haven't been able to find the answer for and I was hoping you could help.
DES would remain invertible—it would still be ...
user3712347
4
votes
2
answers
1k
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What is the intuition behind AES or SPN?
I'm new to cryptography and have just encountered AES and SPN. I would like to know how the S-box, permutation step and the MixColumn step help improve security. It seems to me (perhaps mistakenly) ...
- 408
17
votes
3
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Why is AES not a Feistel cipher?
I am studying for an exam right now. And I wanted to make sure I got this point correct.
AES is not a Feistel cipher because the operations in AES are not invertible.
Is the above statement correct?...
- 273
5
votes
1
answer
1k
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Increase number of rounds for SPN and Feistel ciphers
Read a post on Schneiers blog (and again 2011) about increasing the number of rounds for AES from to "AES-128 at 16 rounds, AES-192 at 20 rounds, and AES-256 at 28 rounds" to raise the security. ...
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