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In this paper an encryption technique using matrix based substitution and diffusion for fast image encoding is discussed. The cryptographic procedure manipulates a two dimensional array (matrix) for substitution and diffusion operations. The procedure facilitates fast conversion of plaintext and images into cipher text and cipher images. The paper describes(More)
Time-varying codes associate variable length code words to letters being encoded depending on their positions in the input string. These codes have been introduced in [8] as a proper extension of L-codes. This paper is devoted to a further study of time-varying codes. First, we show that adaptive Huffman encodings are special cases of encodings by(More)
  • Dragos Trinca
  • 2006
Worldwide symmetric encryption standards such as DES (data encryption standard), AES (advanced encryption standard), and EES (escrowed encryption standard), have been - and some of them still are - extensively used to solve the problem of communication over an insecure channel, but with today's advanced technologies, they seem to not be as secure and fast(More)
In this paper we address two optimization problems arising in the design of genomic assays based on universal tag arrays. First, we address the universal array tag set design problem. For this problem, we extend previous formulations to incorporate antitag-to-antitag hybridiza-tion constraints in addition to constraints on antitag-to-tag hybridization(More)
With the exception of the recently proposed class of cascaded dynamic convolutional cryp-tosystems, all the symmetric cryptosystems studied so far in the literature are static, in the sense that their structure do not change at all during encryption/decryption. In this paper, we propose and analyze a new class of dynamic symmetric cryptosystems, called(More)
Privacy considerations often constrain data mining projects. This paper addresses the problem of association rule mining where transactions are distributed across sources. Each site holds some attributes of each transaction, and the sites wish to collaborate to identify globally valid association rules. However, the sites must not reveal individual(More)
In this paper, we propose new solution methods for designing tag sets for use in universal DNA arrays. First, we give integer linear programming formulations for two previous formalizations of the tag set design problem. We show that these formulations can be solved to optimality for problem instances of moderate size by using general purpose optimization(More)