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<big><big><big><small>Sehr geehrte Damen und Herren, <br>
<br>
<br>
im Rahmen des HGI-Kolloquiums, organisiert vom
Lehrstuhl Kryptologie und IT-Sicherheit (CITS), wird<br>
<br>
<big><u>Pooya Farshim</u></big></small><u><br>
<br>
</u><small>von der <br>
<br>
T</small></big></big></big><big><big><big><small>echnische</small></big></big></big><big><big><big><small>
Universität Darmstadt</small></big></big></big><big><big><big><small><br>
<br>
am <br>
<br>
nächsten <u>Donnerstag, den 12. Januar 2012
um 11.00 Uhr s.t. in Raum ID 03/653<br>
<br>
</u>über folgendes Thema referieren:</small><br>
</big></big></big> <br>
<br>
<hr size="2" width="100%"><big><b>Delegatable
Homomorphic Encryption with Applications to
Secure Outsourcing of Computation</b><br>
<br>
In this talk, we propose a new cryptographic
primitive called Delegatable Homomorphic
Encryption (DHE). This allows a Trusted Authority to
control/delegate the evaluation of circuits over
encrypted data to untrusted workers/evaluators by
issuing tokens. This primitive can be both seen as a
public-key counterpart to Verifiable Computation,
where input generation and output verification are
performed by different entities, or as a
generalisation of Fully Homomorphic Encryption
enabling control over computations on encrypted
data. Our primitive comes with a series of extra
features: 1) there is a one-time setup procedure for
all circuits; 2) senders do not need to be aware of the
functions which will be evaluated on the encrypted
data, nor do they need to register keys; 3) tokens are
independent of senders and receiver; and 4)
receivers are able to verify the correctness of
computation given short auxiliary information
on the input data and the function, independently of
the complexity of the computed circuit. We give a
modular construction of such a DHE scheme from three
components: Fully Homomorphic Encryption (FHE),
Functional Encryption (FE), and a (customised) MAC.
As a stepping stone, we first define Verifiable
Functional Encryption (VFE), and then show how one can
build a secure DHE scheme from a VFE and an FHE scheme.
We also show how to build the required VFE from a
standard FE together with a MAC scheme. All our results
hold in the standard model. Finally, we show how one can
build a verifiable computation (VC) scheme
generically from a DHE. As a corollary, we get the
first VC scheme which remains verifiable even if the
attacker can observe verification results.</big><big><big><br>
</big></big>
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<div class="section"
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class="Apple-style-span" style="color: rgb(0, 53, 96);"> </span></span><span
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word-spacing: 0px;"><span class="Apple-style-span"
style="color: rgb(0, 53, 96);"><big>Der Vortrag beginnt am
Donnerstag um 11.00 Uhr s.t. im ID 03/563.<br>
</big></span></span><br>
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class="Apple-style-span" style="color: rgb(0, 53, 96);"><big>Zu
diesem und sämtlichen weiteren Vorträgen im Rahmen des
HGI-Kolloquiums sind alle Studierenden und
Interessierten herzlich eingeladen! Eine Voranmeldung
ist nicht erforderlich!</big></span></span>
<p><span class="Apple-style-span" style="border-collapse:
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class="Apple-style-span" style="color: rgb(0, 53, 96);"><big>Weitere
Informationen gibt es auf folgender Webseite:<br>
<br>
<a
href="http://hgi.rub.de/hgi/hgi-seminar/aktuelles/">http://hgi.rub.de/hgi/hgi-seminar/aktuelles/</a></big><br>
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<big><big>Beste Grüße, <br>
Saqib A. Kakvi</big></big><br>
<br>
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