[HGI-News-de] HGI Kolloquium am 19.03.2013

[Newsletter des Horst Görtz Instituts]

Sehr geehrte Damen und Herren,

im Rahmen des HGI-Kolloquiums wird Christina Brzuska aus Tel Aviv am
Dienstag, den 19. März 2013 um 11.00 Uhr s.t. in Raum ID 04/653 über
folgendes Thema referieren:

Notions of Black-Box Reductions, Revisited

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Reductions are the common technique to prove security of cryptographic
constructions based on a primitive. They take an allegedly successful
adversary against the construction and turn it into a successful
adversary against the underlying primitive. To a large extent, these
reductions are black-box in the sense that they consider the primitive
and/or the adversary against the construction only via the input-output
behavior, but do not depend on internals like the code of the primitive
or of the adversary. Reingold, Trevisan, and Vadhan (TCC, 2004)
provided a widely adopted framework, called the RTV framework from
hereon, to classify and relate diff erent notions of black-box
reductions. Having precise notions for such reductions is very
important
when it comes to black-box separations, where one shows that black-box
reductions cannot exist. An impossibility result, which
clearly specifi es the type of reduction it rules out, enables us to
identify the potential leverages to bypass the separation. We
acknowledge this by extending the RTV framework in several respects
using a more fi ne-grained approach. First, we capture a type of
reduction -- frequently ruled out by so-called meta-reductions -- which
escapes the RTV framework so far. Second, we consider notions that are
"almost black-box", i.e., where the reduction receives additional
information about the adversary, such as its success probability.
Third,
we distinguish explicitly between e fficient and ineffi cient
primitives
and adversaries, allowing us to determine how relativizing reductions
in
the sense of Impagliazzo and Rudich (STOC, 1989) fit into the picture.
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Zu diesem und sämtlichen weiteren Vorträgen des HGI-Kolloquiums
sind alle Studenten und Interessierten herzlich eingeladen!
Eine Voranmeldung ist nicht erforderlich!

Weitere Informationen gibt es auf folgender Webseite:
http://hgi.rub.de/hgi/hgi-seminar/

Mit freundlichen Grüßen
 Thomas Hupperich & Johannes Hoffmann