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Questions tagged [permutation]

A way, esp. one of several possible variations, in which a set or number of things can be ordered or arranged.

184 questions
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Permutations of pseudorandom data

Assuming a bit string is deemed cryptographically secure, e.g. PRNG using AES in counter mode, can we equally assume any permutation of said bit string is also cryptographically secure? In a more practical sense, using a PRNG with AES in counter…
Thomas
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derangements and permutations in cryptography

Given a partial key for a mono-alphabetic substitution cipher (missing 11 letters), calculate the number $N$ of possible keys, given that no plaintext letter can be mapped to itself. Ordinarily, the number of possible keys would be the number…
guskenny83
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How do we find the last two correspondences in an otherwise known even permutation?

A secret even permutation $P$ of the set of non-negative integers less than $n$ is chosen. That might be a Feisltel cipher with a random key. We are given in sequence the $P(x)$ for $x$ from $0$ to $n-3$, and must output the ordered pair…
fgrieu
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Is it possible to permute a binary vector obliviously?

Lets say A has a binary vector of length n, B has a permutation matrix of size n. Is there a way for B to permute A's vector so that A only learns about the result of permutation and B does not learn about the original vector?
Adam
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Method for creating any involutive permutation

The Fisher-Yates shuffle can produce any permutation of a set of $n$ elements. Is there anything that can do the same for creating an involutive permutation of $n$ elements where $n$ is an even number? This could be used to create involutive…
Melab
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Permutation parity after cycle-walking

Let $E$ be a random even permutation of the set $\{0\dots n-1\}$. We construct a permutation $P$ of the set $\{0\dots m-1\}$, for some $m\le n$, using cycle-walking; that is, computing $P(x)$ is as follows: repeat $x\gets E(x)$ until…
fgrieu
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How to cryptanalyze the message using permution cipher

The message is: ACAUI MMGRC AILEE HKREG EAISW OSTHDS With a grid size of 6 x 6. The forbidden cells are in different rows and different columns, so there are no two forbidden cells in the same line.
Rose
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What's a random involution?

What are the properties of random involution? What is the difference between random involution and random permutation?
wurst
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If you iterate a cryptographic permutation long enough will you map the input to itself?

Given a cryptographic permutation $\{0,1\}^n \rightarrow \{0,1\}^n$ does it follow that after some number of iterations you must eventually map the input to itself?
Jack Fleming
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Can both substitution and transposition ciphers be thought of as permutations?

I came across this problem to 'explain why both substitution and transposition ciphers can be thought of as permutations' and I cannot come up with an explanation to how substitution ciphers can be thought of as permutations. Can somebody provide an…
hwkd
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How to find k evenly-distributed elements from the set of all n！ permutations over n alternatives?

Let $C=\{ c_1, c_2, \cdots,c_n \}$ be a set of $n$ alternatives and $T$ be the set of all strict complete orderings on $C$. For any two $t_1$ and $t2$ in $T$, their (Kendal-tau) distance $d(t_1, t_2)$ is defined as the number of pairwise…
Joe Zhou
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