[HGI-News-de] HGI Kolloquium 03.12 - Attacking Power Generators Using Unravelled Linearization

[Newsletter des Horst Görtz Instituts]

Hallo,

im Rahmen des HGI Kolloquiums "Aktuelle Themen der IT-Sicherheit" wird 
am kommenden Donnerstag der folgende Vortrag angeboten:

Mathias Herrmann
* Attacking Power Generators Using Unravelled Linearization *

Termin:
Donnerstag, den 3. Dezember um 11.00 Uhr (*s.t.*)
Raum: IC 4/39

Interessierte sind herzlichst eingeladen!


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Abstract:
We look at iterated power generators $s_i = s_{i-1}^e \mmod N$ for a 
random seed $s_0 \in \Z_N$ that in each iteration output a certain 
amount of bits. We show that heuristically an output of $(1-\frac 1 
e)\log N$ most significant bits per iteration allows for efficient 
recovery of the whole sequence. This means in particular that the 
Blum-Blum-Shub generator should be used with an output of less than half 
of the bits per iteration and the RSA generator with $e=3$ with less 
than a $\frac 1 3$-fraction of the bits. Our method is lattice-based and 
introduces a new technique, which combines the benefits of two 
techniques, namely the method of linearization and the method of 
Coppersmith for finding small roots of polynomial equations. We call 
this new technique unravelled linearization.
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Vorankündigung: 10. Dezember 2009: Michael Silbermann (EmSec), Security 
Analysis of Contactless Payment Systems in Practice - 14. Januar 2010, 
(!10:15!): Wilfried Karden (Innenministerium NRW), Wirtschaftsspionage - 
21. Januar 2010: Orr Dunkelman (Weizmann Institute of Science), KATAN & 
KTANTAN - A Family of Small and Efficient Hardware-Oriented Block 
Ciphers - 28. Januar 2010: Daehyun Strobel (EmSec), TBA - 4. Februar 
2010: Florian Kerschbaum (SAP), Security Challenges in Supply Chain 
Management.

Informationen über die nächsten geplanten Vorträge im Rahmen des HGI 
Kolloquiums sind auch im Web zu finden:
http://www.hgi.rub.de/hgi/hgi-seminar/aktuelles


Viele Grüße,
Georg Becker und Timo Kasper