From d9317a77ce72f63188686ca1194587a370cf5db1 Mon Sep 17 00:00:00 2001 From: Tobias Eidelpes Date: Wed, 15 Jun 2022 15:55:33 +0200 Subject: [PATCH] Add solution for 4e --- exam/ex.tex | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/exam/ex.tex b/exam/ex.tex index ad85d18..c9f5802 100644 --- a/exam/ex.tex +++ b/exam/ex.tex @@ -193,7 +193,14 @@ Finding a minimum-weight solution to $s=zH$ given $s$ and $H$ is $\mathsf{NP}$-hard. - \item \TODO + \item The private key in LEDAcrypt consists of two binary matrices $Q$ and + $H$. The public key is constructed from the matrix $L=Q\cdot H$. The + security of the scheme relies on the fact that obtaining the original + information from a perturbed codeword is hard unless the factorization of + the public key ($Q\cdot H$) is known. If the aforementioned problem of + decoding linear codes has a polynomial-time solution, an attacker will + also easily be able to obtain the factorization of the public key. If that + was possible, the scheme would be broken. \item \TODO