Countering Cryptographic Attacks

By reading Camellia Design and Analysis document following is my understanding about few cryptographic attacks from designer point of view.

1. Differential and Linear Crypt-analysis. Number of Active S-boxes along-with the Differential and Linear probabilities of S-box contributes towards resistance against these attacks which also depends upon the branch number of the P Box. (Diffusion layer).

2. Truncated Differential. If there does not exist an iterated truncated differential with higher probability than exhaustive keysearch then cipher is safe against this type of attack. (I need to learn more about how to counter this attack)

3. Impossible Differential. There exist one 5 round impossible differential in feistel cipher with bijective F function. So cipher with more than 10 rounds will have a good security margin against this attack.

4. Boomrang Attack. This uses two differentials and security against these again depends upon number of active S-boxes along-with the Differential probability of the S-box.

5. Higher Order Differential. To resist this attack, Degree of the Boolean polynomials of the S-Boxes should be higher.

6. Equivalent Keys. Use of original key as one round subkey reduces the chance of Equivalent key classes.

7. Slide Attack. Ciphers with iterated identical round functions are suspect-able to such attack however use of Pre and Post whitening keys provide resistance against this attack.(assuming Pre / Post whitening keys have been generated from a strong keyschedule)

Do i have right understanding countering these attacks?

• ...and your question is? Commented Jun 10, 2016 at 18:16
• You expect us to judge your understanding from 8 short phrases? Commented Jun 11, 2016 at 6:15
• please guide if you find something drastically wrong in these short sentences. Commented Jun 11, 2016 at 8:11

Differential and Linear Crypt-analysis. Number of Active S-boxes along-with the Differential and Linear probabilities of S-box contributes towards resistance against these attacks which also depends upon the branch number of the P Box. (Diffusion layer)

it is not only the branch number that influences on the number of active s-boxes, the cells permutation has a role, different permutations have different number of active s-box over rounds such as in skinny and midori cases.ref

Impossible Differential. There exist one 5 round impossible differential in feistel cipher with bijective F function. So cipher with more than 10 rounds will have a good security margin against this attack

in term of SPN ciphers , according to this paper, the existence of impossible differential up to 6 rounds which are strongly related to the linear transformation properties.

Boomrang Attack. This uses two differentials and security against these again depends upon number of active S-boxes along-with the Differential probability of the S-box.

a new measure analysis called boomerang connectivity table of S-box provides insights on boomerang crypt analysis which provides a fundamental understanding how the S-box properties counter the boomerang attack. ref

Higher Order Differential. To resist this attack, Degree of the Boolean polynomials of the S-Boxes should be higher.

using larger S-box with higher algebraic immunity provides a counter to higher order differential.

what about integral crypt analysis (division property of sbox) ?