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6 votes
0 answers
130 views

Bent vectors and $\pm 1$ eigenvectors with respect to non-Sylvester Hadamard matrices

A Hadamard matrix is an $n\times n$-matrix $H$ where each entry in $H$ is $\pm 1$ and where $H/\sqrt{n}$ is orthogonal. It is well-known that if $H$ is an $n\times n$-Hadamard matrix, then $n<3$ or ...
Joseph Van Name's user avatar
2 votes
0 answers
78 views

Partitions of bent vectors

Let $H=\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 1 \\ 1 & -1\end{bmatrix}.$ Let $A^{\otimes N}$ denote the tensor product of the matrix $A$ with itself taken $N$ times. We say that a vector $v$ of ...
Joseph Van Name's user avatar
3 votes
0 answers
67 views

Efficiently finding solutions to the Rainbow cryptosystem using quotient spaces

Repost of a mathematics stackexchange question here as this concerns my research and it went unanswered on there. In this paper, Ward Beullens gives another way to look at the Rainbow cryptosystem. In ...
Saegusa's user avatar
  • 173
10 votes
1 answer
1k views

Cryptographic Secret Santa

Is there a protocol for conducting a Secret Santa without a central authority? Precisely, we want to sample uniformly a permutation that has no one-cycles and reveal to each member his or her ...
Vodka's user avatar
  • 101
1 vote
1 answer
92 views

Dual lattices up to a q scaling factor

In this paper : https://eprint.iacr.org/2011/501.pdf There is an equality page 10, in the second paragraph considered by the authors as "easy to check". If someone could explain to me why the set at ...
Ievgeni's user avatar
  • 215
1 vote
1 answer
133 views

Reduced echelon form of sparce matrices and constructing hash function

Let $G$ be a $d$-regular graph, and $A$ be the incidence matrix of $G$. Also suppose $B$ is a reduced echelon form of $A$ such that computations are in $\mathbb F_2$. Given matrix $B$, can we find ...
Meysam Ghahramani's user avatar
0 votes
0 answers
262 views

Lattice basis reductions and finding minimal values

While reading several articles about lattice basis reduction I am left with a few questions. For one, I came across this piece of text Let $\alpha$ and $\beta \in \mathbb{R}$. Also let $X>0$ and $...
Zoe's user avatar
  • 1
6 votes
1 answer
453 views

Computing the correlation between two vectors without divulging them

Alice and Bob respectively know a vector of $N$ real numbers $u$ and $v$. They would both like to know $\rho = \langle u,v \rangle/N$ but Alice does not want Bob to gain anymore information about $u$ ...
Arthur B's user avatar
  • 1,902
1 vote
1 answer
737 views

Matrix Conjugates over Finite Fields

Thinking about Diffe-Hillman for matrices brought me to the following question. Given $\mathbb{F}_{p^k}$ the finite field with $p^k$ elements when can we find non-trivial solutions to $\begin{...
B. Bischof's user avatar
  • 4,842