9,648 research outputs found
Security of a biometric identity-based encryption scheme
Biometric identity-based encryption (Bio-IBE) is a kind of fuzzy
identity-based encryption (fuzzy IBE) where a ciphertext encrypted under an
identity w' can be decrypted using a secret key corresponding to the identity w
which is close to w' as measured by some metric. Recently, Yang et al. proposed
a constant-size Bio-IBE scheme and proved that it is secure against adaptive
chosen-ciphertext attack (CCA2) in the random oracle model. Unfortunately, in
this paper, we will show that their Bio-IBE scheme is even not chosen-plaintext
secure. Specifically, user w using his secret key is able to decrypt any
ciphertext encrypted under an identity w' even though w is not close to w'.Comment: Journal version of the paper will be appearing in International
Journal of Network Securit
Electric Fields and Chiral Magnetic Effect in Cu + Au Collisions
The non-central Cu + Au collisions can create strong out-of-plane magnetic
fields and in-plane electric fields. By using the HIJING model, we study the
general properties of the electromagnetic fields in Cu + Au collisions at 200
GeV and their impacts on the charge-dependent two-particle correlator
(see main text for
definition) which was used for the detection of the chiral magnetic effect
(CME). Compared with Au + Au collisions, we find that the in-plane electric
fields in Cu + Au collisions can strongly suppress the two-particle correlator
or even reverse its sign if the lifetime of the electric fields is long.
Combining with the expectation that if is induced by
elliptic-flow driven effects we would not see such strong suppression or
reversion, our results suggest to use Cu + Au collisions to test CME and
understand the mechanisms that underlie .Comment: V1: 7 pages, 8 figures. V2: Add 2 new figures. Published versio
Incompressible Limit of Solutions of Multidimensional Steady Compressible Euler Equations
A compactness framework is formulated for the incompressible limit of
approximate solutions with weak uniform bounds with respect to the adiabatic
exponent for the steady Euler equations for compressible fluids in any
dimension. One of our main observations is that the compactness can be achieved
by using only natural weak estimates for the mass conservation and the
vorticity. Another observation is that the incompressibility of the limit for
the homentropic Euler flow is directly from the continuity equation, while the
incompresibility of the limit for the full Euler flow is from a combination of
all the Euler equations. As direct applications of the compactness framework,
we establish two incompressible limit theorems for multidimensional steady
Euler flows through infinitely long nozzles, which lead to two new existence
theorems for the corresponding problems for multidimensional steady
incompressible Euler equations.Comment: 17 pages; 2 figures. arXiv admin note: text overlap with
arXiv:1311.398
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