Homomorphic Hashing Based on Elliptic Curve Cryptography

For avoiding the exposure of plaintexts in cloud environments, some homomorphic hashing algorithms have been proposed to generate the hash value of each plaintext, and cloud environments only store the hash values and calculate the hash values for future needs. However, longer hash value generation time and longer hash value summary time may be required by these homomorphic hashing algorithms with higher security strengths. Therefore, this study proposes a homomorphic hashing based on elliptic curve cryptography (ECC) to provide a homomorphic hashing function in accordance with the characteristics of ECC. Furthermore, mathematical models and practical cases have been given to prove the proposed method. In experiments, the results show that the proposed method have higher efficiency with different security strengths.Comment: in Chinese languag

簡單快速雲端階層式組織授權之應用

[[abstract]]本論文提出一套應用在雲端運算中，使階層式結構中群組間進行資料授權能夠簡單快速方法。本方法中，結構中群組有一把公開金鑰PK及私密金鑰SK，並且將群組私密金鑰SK，用直接上屬群組公開金鑰加密產生公開參數R。利用直屬結構表公開各群組公開金鑰，相對公開參數R及直接上屬群組等資訊。 群組會將資料用群組私密金鑰SK所導出的加密金鑰，加密該文件，並將其上傳至雲端中。當被授權的群組(即上屬群組們)，則透過對直屬結構表中公開數值，遞迴路徑運算出該群組私密金鑰SK進而解密該資料。本論文所提機制亦與AKL、Lo-Hwang-Liu、Chu-Hsing Lin三位所提機制在多個面象(運作成員、效率、新成員加入及離開等)做比較，本論文具不用CA(Certificate Authority，憑證管理中心)、運算簡單、具當階層式結構擴大較少公開參數改變的優點。[[sponsorship]]中華民國資訊管理學會[[conferencetype]]國際[[conferencedate]]20150523~20150523[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]台北市, 台

本館無線網路認證系統異動

Ecological studies need accurate environmental data such as vegetation characterization, landscape structure and organization, to predict and explain the spatial distribution of biodiversity. Few ecological studies use remote sensing data to assess the biophysical or structural properties of vegetation to understand species distribution. To date, synthetic aperture radar (SAR) data have seldom been used for ecological applications. However, these sensors provide data allowing access to the inner structure of vegetation which is a key information in ecology. The objective of this article is to compare the predictive power of ecological habitat structure variables derived from a TerraSAR-X image, an aerial photograph and a SPOT-5 image for species distribution. The test was run with a hedgerow network in Brittany and assessed the spatial distribution of the forest ground carabid beetles which inhabit these hedgerows. The results confirmed that radar and optical images can be indifferently used to extract hedgerow network and derived landscape metrics (hedgerow density, network grain) useful to explain the spatial distribution of forest carabid beetles. In comparison with passive optical remotely sensed data, VHSR SAR images provide new data to characterize vegetation structure and more particularly hedgerow canopy cover, a variable known to explain the spatial distribution of carabid beetles in an agricultural landscape, but not yet quantified at a fine scale. The hedgerow canopy cover derived from the SAR image is a strong predictor of the abundance of forest carabid beetles at two scales i.e., a local scale and a landscape scale

密碼學應用

[[abstract]]1042密碼學應