Most public blockchains are riddled with problems such as centralization trends and increasing processing fees, along with scalability and throughput bottlenecks. In an attempt to mitigate these problems, we propose a new blockchain design: the crypto-commodity protocol. Unlike crypto-currencies whose valuation fluctuates due to market volatility, crypto-commodity has an intrinsic value that is not influenced by any external factor: digital commodity owned by users is the number of bytes that can be consumed in the form of block records. It is inherently spam resistant by virtue of its design, and does not rely upon processing fees to achieve this goal. We suggest to improve throughput scalability through a dynamic block size adaptive to the network's hashing power. To combat centralization trends, we have augmented proof of work with two refinements: public key based mining history and proof of consumption. Our design also guarantees monotonous timestamps and incorporates a reward scheme that incentivizes processing of records without fee.
Smart contracts have been established as the standard mechanism for online crypto-currency transactions in blockchains such as Bitcoin and Ethereum. The application scope of smart contracts is predicted to expand beyond crypto-currency in upcoming years, and this emerging technology is likely to play a significant role in other major domains. Smart contracts are usually created using a special purpose programming language. In this paper, we explore an alternative mechanism based on propositional calculus, using multisignature and lock-based boolean variables. Higher order boolean quantifiers have been avoided, and from a security standpoint, the design is deliberately kept Turing-incomplete to guarantee bounded runtime and well-defined termination paths for any valid smart contract (for homogeneous locks, our validation checks run in linear time for best case and quadratic time for worst case). Keeping in mind a widening scope for smart contracts, the applicability of our design is not confined to blockchain transactions, but can be easily integrated into other application domains.
The login time distribution in e-mail servers are studied. The distribution seems to be decaying in a scale-free manner with a decay exponent lying between 1.2 and 2.2, varying from server to server. A simple mean-field theory shows that this distribution has a decay exponent 2.
.The early 2000’s saw the explosive growth of Information Technology, computing devices, the internet and all sorts of information systems. Today there is no aspect of our lives that is yet untouched by these devices. Commerce, trade, transportation, communication, education all depend on information systems in more than a few ways. But more reliance on information technology also means greater importance of securing them against threats and risks. In this article we give an overview of information-system security and some of its basic tools and technologies.
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