Questions tagged [differential-analysis]
Differential cryptanalysis is a form of cryptanalysis which studies cryptographic algorithms by observing how differences in input affect differences in output.
154 questions
2 votes
1 answer
84 views
A question on Biham and Shamir's paper on differential cryptanalysis for 16-round DES
In the paper for breaking 16-round DES with differential cryptanalysis, on pages 79-81 in the document I linked, the authors describe a technique on adding an initial round to the 15 round attack. ...
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2 votes
1 answer
183 views
How to find high probability output differences for modular addition in differential cryptanalysis?
In my introduction to cryptography course I only ever did differential cryptanalysis on ciphers which were completly linear. Now I am analyzing a hash function, where I have to propagate XOR ...
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2 votes
1 answer
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Clarification on Construction of the HATF and HOD Usage in "Revisiting Higher-Order Differential-Linear Attacks from an Algebraic Perspective"
I'm currently reading an interesting paper, "Revisiting Higher-Order Differential-Linear Attacks from an Algebraic Perspective", and I had a couple of questions in Section 4.1, which ...
4 votes
0 answers
155 views
Is the NH hash family (from UMAC) AXU?
For any positive integer $k$, let $\boxplus_k$ be addition on $k$-bit unsigned integers and $\boxminus_k$ be subtraction on $k$-bit unsigned integers. Let $\operatorname{NH}_w((X,Y),(a,b)) = (a \...
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2 votes
1 answer
136 views
What are realistic can-run-on-my-laptop linear and differential attacks on reduced-round AES?
I'd like to teach linear and differential cryptanalysis using AES as an example. I'm guessing there must be a number of rounds that are realistic to attack on a laptop. I'm also interested in other ...
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1 vote
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Effect of summand XOR-difference on the sum
Suppose I have two unknown elements of a ring $\mathbb{Z}_{2^n}$: $a$ and $b$. Their sum $s_1 = a+b$ is known. Let $x$ be some fixed known value with $m < n$ bits set to 1. What could I say about ...
- 275
0 votes
0 answers
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Designing simple functions with a high degree of mixing
In designing a MAC algorithm from scratch (don't lecture me, please), I was dissatisfied with what seemed to be patterns in the tags it generated. I figured this was a result of linearity or what have ...
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3 votes
1 answer
145 views
How do I find the optimal number of rounds needed so that my block cipher is secure?
I am new to cryptanalysis for SPN. In context of linear and differential cryptanalysis, I would like to know the following. How does one find the number of active S-boxes in a block cipher? Why does ...
8 votes
1 answer
1k views
How can Blowfish be resistant against differential cryptanalysis if it doesn't have S-boxes tuned for that?
The S-boxes used in DES were carefully tuned for resistance against differential cryptanalysis, a technique not known to the public at that time but known to designers of DES. It was later discovered ...
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1 vote
1 answer
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Is there any notion of key-recovery attacks security (perhaphs using games) that is equivalent to IND-CPA?
I am talking about Symmetric Cryptography only in the following. We know that Semantic Security (in the presence of eavesdropper) implies security against message recovery (in the presence of ...
1 vote
0 answers
99 views
New Impossible Differential Attacks on AES reduce time complexity
I am interested in the following snippet from the paper New Impossible Differential Attacks on AES. Analysis of Steps 3–4 of the 7-Round Attack in the 8-Round Attack The most time consuming steps of ...
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3 votes
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83 views
improved impossible differential crpytanalysis of 6-round rijndael
I'm studying the paper: "Improved Impossible Differential Cryptanalysis of Rijndael and Crypton". I've got two questions: Please explain the calculation performed for step 5? Step 4 ...
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2 votes
0 answers
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Can a differential attack on FEAL4 yield multiple valid keys?
For my version of this attack I used the FEAL4 version depicted here http://theamazingking.com/crypto-feal.php and in the book "Applied Cryptanalysis Breaking Ciphers in the Real World -- Mark ...
1 vote
1 answer
88 views
Differential uniformity of vectorial Boolean function
What could we say about differential uniformity of (a vectorial Boolean function) $F = f+g \pmod 2$ (i.e. XOR) in terms of differential uniformity of $f$ and $g$?
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0 votes
1 answer
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Heys Differential Cryptanalysis Question
I'm wondering if anyone is aware of the best input difference to input into the system Heys outlines in his paper (http://www.cs.bc.edu/~straubin/crypto2017/heys.pdf) to achieve a high probability ...
