From ae078689a6e0d11b692d6fe81f5d4a8761c3c696 Mon Sep 17 00:00:00 2001 From: Tobias Eidelpes Date: Tue, 14 Jun 2022 16:49:05 +0200 Subject: [PATCH] Add solution for 2g --- exam/ex.tex | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/exam/ex.tex b/exam/ex.tex index 0742647..52c7295 100644 --- a/exam/ex.tex +++ b/exam/ex.tex @@ -137,7 +137,13 @@ number of evaluations an attacker has to make to obtain a repeated nonce is $2^{96/2} = 2^{48}$. - \item \TODO + \item After $2^b = 2^{62}$ forgery attempts, the attacker has exhausted the + keyspace of the tag because the tag $T$ is of size $\unit[62]{bits}$. The + distinguisher checks continuously if the current tag matches the + ciphertext. If it does not, the tag is incremented by one until $2^{62}$ + queries have been made. Eventually, the distinguisher will get the valid + tag and is then able to identify if it is in the real world or in the + ideal world. \item \TODO