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Cryptanalysis of an Image Encryption Scheme Based on a Compound Chaotic Sequence
Recently, an image encryption scheme based on a compound chaotic sequence was
proposed. In this paper, the security of the scheme is studied and the
following problems are found: (1) a differential chosen-plaintext attack can
break the scheme with only three chosen plain-images; (2) there is a number of
weak keys and some equivalent keys for encryption; (3) the scheme is not
sensitive to the changes of plain-images; and (4) the compound chaotic sequence
does not work as a good random number resource.Comment: 11 pages, 2 figure
Double neutron/proton ratio of nucleon emissions in isotopic reaction systems as a robust probe of nuclear symmetry energy
The double neutron/proton ratio of nucleon emissions taken from two reaction
systems using four isotopes of the same element, namely, the neutron/proton
ratio in the neutron-rich system over that in the more symmetric system, has
the advantage of reducing systematically the influence of the Coulomb force and
the normally poor efficiencies of detecting low energy neutrons. The double
ratio thus suffers less systematic errors. Within the IBUU04 transport model
the double neutron/proton ratio is shown to have about the same sensitivity to
the density dependence of nuclear symmetry energy as the single neutron/proton
ratio in the neutron-rich system involved. The double neutron/proton ratio is
therefore more useful for further constraining the symmetry energy of
neutron-rich matter
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