Haseeb Ahmad

Clustering by fast search and find of density peaks via heat diffusion

Clustering by fast search and find of density peaks (CFSFDP) is a novel algorithm that efficiently discovers the centers of clusters by finding the density peaks. The accuracy of CFSFDP depends on the accurate estimation of densities for a given dataset and also on the selection of the cutoff distance (dc). Mainly, dc is used to calculate the density of each data point and to identify the border points in the clusters. CFSFDP necessitates using different methods for estimating the densities of different datasets and the estimation of dc largely depends on subjective experience. To overcome the limitations of CFSFDP, this paper presents a method for CFSFDP via heat diffusion (CFSFDP-HD). CFSFDP-HD proposes a nonparametric method for estimating the probability distribution of a given dataset. Based on heat diffusion in an infinite domain, this method accounts for both selection of the cutoff distance and boundary correction of the kernel density estimation. Experimental results on standard clustering benchmark datasets validate the robustness and effectiveness of the proposed approach over CFSFDP, AP, mean shift, and K-means methods.

Fuzzy encryption in cloud computation: efficient verifiable outsourced attribute-based encryption

Attributed-based encryption (ABE) is a promising cryptographic access control mechanism with a rich expressiveness of ABE policies. Due to the high complexities of encryption and decryption, users are burdened with large computation cost. Fortunately, outsourcing technologies can be used to reduce the computation overhead for the ABE schemes. In the recent decade, the achievements of the outsourced ciphertext-policy ABE (CP-ABE) schemes are inspiring. But, the outsourcing encryption algorithms for CP-ABE schemes are not addressed properly since the encryption exponents are dynamic. In this paper, we present an efficient outsourced CP-ABE scheme with checkability, where the number of the exponential operations in the encryption can be reduced to a constant by introducing a blinding algorithm. Meanwhile, the ciphertext size is not increased. Furthermore, to guarantee the correctness of our scheme, we provide the verification mechanism based on a collision-resistance hash function, which allows the users to efficiently check the validity of messages and outsourced computation results. Besides, the proposed scheme is secure against replayable chosen ciphertext attacks based on Green’s outsourcing security model. Intensive experiments are carried out to illustrate the efficiency of the proposed scheme.

All exceptional groups of lie type have minimal logarithmic signatures

As a special type of factorization of finite groups, logarithmic signature (LS) is used as the main component of cryptographic keys for secret key cryptosystems such as PGM and public key cryptosystems like

Cost effective scheme for OLT in next generation passive optical access network based on noise free optical multi carrier

MST_1, MST_2

Primitives towards verifiable computation: a survey

MST1,MST2 and

Minimum length key in MST cryptosystems

MST_3