Chosen Ciphertext Security via Correlated Products
Speaker: Alon Rosen , IDC Herzliya
Date: August 1 2008
Time: 10:30AM to 12:30PM
Location: 32-G449, Patil/Kiva
Host: Silvio Mical, CSAIL
Contact: Be, 3-6098, imbe@mit.edu
Relevant URL: In this talk I will present a new notion of security, called
one-wayness under correlated products. The question we are interested
in is what are necessary and sufficient conditions for a function f
and a distribution on inputs (x1,...,xk), so that the function
(f(x1),...,f(xk)) is one-way. The main motivation of this study is the
construction of public-key encryption schemes that are secure against
chosen-ciphertext attacks (CCA). We show that any collection of
injective trapdoor functions that is secure under very natural
correlated products can be used to construct a CCA-secure public-key
encryption scheme. The construction is simple, black-box, and admits a
direct proof of security.
We provide evidence that security under correlated products is
achievable by demonstrating that any collection of lossy trapdoor
functions, a powerful primitive introduced by Peikert and Waters (STOC
'08), yields a collection of injective trapdoor functions that is
secure under the above mentioned natural correlated products. Although
we eventually base security under correlated products on lossy
trapdoor functions, we argue that the former notion is potentially
weaker as a general assumption. Specifically, there is no
fully-black-box construction of loss trapdoor functions from trapdoor
functions that are secure under correlated products.
Joint work with Gil Segev.
See other events that are part of Cryptography and Information Security Seminars 2007/2008
See other events happening in August 2008
