Date: 2011/1/14 (Fri) 15F30`17F00Place: Collaboration Room #7 (Information Science Building, 5th floor)
Name: Isamu TeranishiNEC Corporation, Internet Systems Research Laboratories.
Title: Signatures Resilient to Continual Leakage on Memory and Computation
Abstract:
Cryptographic schemes have traditionally been modeled under the
assumption that the secret key is
hidden completely within a device. However, cryptographic engineering
has taught us that devices are
not perfect and can leak information about the key, via ''side channels'',
such as timing, radiation,
or power consumption associated with computations.
We propose a signature scheme which is secure even if a large fraction
of the secret keys is leaked.
The fraction of information that our scheme allows to leak is optimal in
the sense that no signature
scheme can be secure against more leakage than ours.
Moreover, our scheme is secure even when leaked information is related
with the randomness used in
signing. Known schemes satisfied this property only in the random oracle
model, or only when the
fraction of leakage was not optimal while our scheme does not require
such an assumption or condition.
Our scheme also has a key update procedure, by which one can get new key
without leakage. Our scheme
is secure under SXDH assumption in the standard model.
