In this paper, we propose a novel video encryption scheme based on multiple digital chaotic systems, which is called CVES (Chaotic Video Encryption Scheme). CVES is independent of any video compression algorithms, and can provide high security for real-time digital video with fast encryption speed, and can be simply realized both by hardware and software. What's more, CVES can be extended to support random retrieval of cipher-video with considerable maximal time-out; the extended CVES is called RRS-CVES (Random-RetrievalSupported CVES). Essentially speaking, CVES is a universal fast encryption system and can be easily extended to other real-time applications. In CVES, 2 n chaotic maps are used to generate pseudo-random signal to mask the video, and to make pseudo-random permutation of the masked video. Another single chaotic map is employed to initialize and control the above 2 n chaotic maps. Detailed discussions are given to estimate the performance of CVES/RRS-CVES, respectively from the viewpoints of speed, security, realization and experiments.

SummaryNeovascularization (NV), as a cardinal complication of several ocular diseases, has been intensively studied, and research has shown its close association with inflammation and immune cells. In the present study, the role of interleukin-17A (IL-17A) in angiogenesis in the process of ocular NV both in vivo and in vitro was investigated. Also, a paracrine role of IL-17A was demonstrated in the crosstalk between endothelial cells and macrophages in angiogenesis. In the retinas of mice with retinopathy of prematurity, the IL-17A expression increased significantly at postnatal day 15 (P15) and P18 during retinal NV. Mice given IL-17A neutralizing antibody (NAb) developed significantly reduced choroidal NV and retinal NV. Studies on vascular endothelial growth factor (VEGF) over-expressing mice suggested that IL-17A modulated NV through the VEGF pathway. Furthermore, IL-17A deficiency shifted macrophage polarization toward an M2 phenotype during retinal NV with significantly reduced M1 cytokine expression compared with wild-type controls. In vitro assays revealed that IL-17A treated macrophage supernatant gave rise to elevated human umbilical vascular endothelial cell proliferation, tube formation and VEGF receptor 1 and receptor 2 expression. Therefore, IL-17A could potentially serve as a novel target for treating ocular NV diseases. The limitation of this study involved the potential mechanisms, such as which transcription accounted for macrophage polarization and how the subsequent cytokines were modulated when macrophages were polarized. Further studies need to be undertaken to definitively determine the extent to which IL-17A neutralizing anti-angiogenic activity depends on macrophage modulation compared with anti-VEGF treatment.

E. Alvarez et al. presented a new chaotic encryption approach recently. But soon G. Alvarez et al. broke it with four cryptanalytic methods and found some other weaknesses. In this letter we point out why the original scheme is so vulnerable to the proposed four attacks. The chief reasons are two essential defects existing in the original scheme. Based on such a fact, we present an improved encryption scheme to obtain higher security. The cryptographic properties of the improved scheme are studied theoretically and experimentally in detail.

H. Zhou et al. have proposed a chaotic encryption scheme, which is based on a kind of computerized piecewise linear chaotic map (PWLCM) realized in finite computing precision. In this paper, we point out that Zhou's encryption scheme is not secure enough from strict cryptographic viewpoint. The reason lies in the dynamical degradation of the computerized piecewise linear chaotic map employed by H. Zhou et al. The dynamical degradation of the computerized chaos induces many weak keys to cause large information leaking of the plaintext. In addition, we also discuss three simple countermeasures to enhance the security of Zhou's cryptosystem, but none of them can essentially enhance the security.PACS : 05.45.Vx/Pq