The demand for data security schemes has increased with the significant advancement in field of computation and communication networks. We propose a novel three-step text encryption scheme that provable against attacks such as key attack statistical attack. proposed is based on Pell sequence elliptic curves, where at first step plain diffused to get meaningless by applying cyclic shift symbol s...

Multiple encryption—the practice of composing a blockcipher several times with itself under independent keys—has received considerable attention of late from the standpoint of provable security. Despite these efforts proving definitive security bounds (i.e., with matching attacks) has remained elusive even for the special case of triple encryption. In this paper we close the gap by improving bo...

—Chebyshev polynomials based public key cryptosystem (CPPKC), proposed by L. Kocarev in 2003, has emerged as a new research field in cryptography and attracted a lot of attentions in recent years. Although provable security in traditional public key cryptosystem has already been developed about twenty years, no relevant security proof research has been found about CPPKC. Aiming at the disabili...

We show that public-key bit encryption schemes which support weak (i.e., compact) homomorphic evaluation of any sufficiently “sensitive” collection of functions cannot be proved message indistinguishable beyond AM ∩ coAM via general (adaptive) reductions, and beyond statistical zero-knowledge via reductions of constant query complexity. Examples of sensitive collections include parities, majori...

Many modern block ciphers are constructed based on the paradigm of substitution-permutation networks (SPNs). But, somewhat surprisingly—especially in comparison with Feistel networks, which have been analyzed by dozens of papers going back to the seminal work of Luby and Rackoff—there are essentially no provable-security results about SPNs. In this work, we initiate a comprehensive study of the...

The emergence of computing environments where smart devices are embedded pervasively in the physical world has made possible many interesting applications and has triggered several new research areas. Mobile ad hoc networks (MANET), sensor networks and radio frequency identification (RFID) systems are all examples of such pervasive systems. Operating on an open medium and lacking a fixed infras...

Title of dissertation: PROVABLE SECURITY FOR CRYPTOCURRENCIES Andrew Miller, Doctor of Philosophy, 2016 Dissertation directed by: Professor Jonathan Katz and Professor Elaine Shi Department of Computer Science The past several years have seen the surprising and rapid rise of Bitcoin and other “cryptocurrencies.” These are decentralized peer-to-peer networks that allow users to transmit money, t...