159 research outputs found
Chosen-plaintext attack of an image encryption scheme based on modified permutation-diffusion structure
Since the first appearance in Fridrich's design, the usage of
permutation-diffusion structure for designing digital image cryptosystem has
been receiving increasing research attention in the field of chaos-based
cryptography. Recently, a novel chaotic Image Cipher using one round Modified
Permutation-Diffusion pattern (ICMPD) was proposed. Unlike traditional
permutation-diffusion structure, the permutation is operated on bit level
instead of pixel level and the diffusion is operated on masked pixels, which
are obtained by carrying out the classical affine cipher, instead of plain
pixels in ICMPD. Following a \textit{divide-and-conquer strategy}, this paper
reports that ICMPD can be compromised by a chosen-plaintext attack efficiently
and the involved data complexity is linear to the size of the plain-image.
Moreover, the relationship between the cryptographic kernel at the diffusion
stage of ICMPD and modulo addition then XORing is explored thoroughly
Cryptanalysis of a family of self-synchronizing chaotic stream ciphers
Unimodal maps have been broadly used as a base of new encryption strategies.
Recently, a stream cipher has been proposed in the literature, whose keystream
is basically a symbolic sequence of the (one-parameter) logistic map or of the
tent map. In the present work a thorough analysis of the keystream is made
which reveals the existence of some serious security problemsComment: 10 pages, 6 figure
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