1,933 research outputs found
The Evolution of Embedding Metadata in Blockchain Transactions
The use of blockchains is growing every day, and their utility has greatly
expanded from sending and receiving crypto-coins to smart-contracts and
decentralized autonomous organizations. Modern blockchains underpin a variety
of applications: from designing a global identity to improving satellite
connectivity. In our research we look at the ability of blockchains to store
metadata in an increasing volume of transactions and with evolving focus of
utilization. We further show that basic approaches to improving blockchain
privacy also rely on embedding metadata. This paper identifies and classifies
real-life blockchain transactions embedding metadata of a number of major
protocols running essentially over the bitcoin blockchain. The empirical
analysis here presents the evolution of metadata utilization in the recent
years, and the discussion suggests steps towards preventing criminal use.
Metadata are relevant to any blockchain, and our analysis considers primarily
bitcoin as a case study. The paper concludes that simultaneously with both
expanding legitimate utilization of embedded metadata and expanding blockchain
functionality, the applied research on improving anonymity and security must
also attempt to protect against blockchain abuse.Comment: 9 pages, 6 figures, 1 table, 2018 International Joint Conference on
Neural Network
Threats and countermeasures for network security
In the late 1980's, the traditional threat of anonymous break-ins to networked computers was joined by viruses and worms, multiplicative surrogates that carry out the bidding of their authors. Technologies for authentication and secrecy, supplemented by good management practices, are the principal countermeasures. Four articles on these subjects are presented
BlockPKI: An Automated, Resilient, and Transparent Public-Key Infrastructure
This paper describes BlockPKI, a blockchain-based public-key infrastructure
that enables an automated, resilient, and transparent issuance of digital
certificates. Our goal is to address several shortcomings of the current TLS
infrastructure and its proposed extensions. In particular, we aim at reducing
the power of individual certification authorities and make their actions
publicly visible and accountable, without introducing yet another trusted third
party. To demonstrate the benefits and practicality of our system, we present
evaluation results and describe our prototype implementation.Comment: Workshop on Blockchain and Sharing Economy Application
Reexamination of Quantum Bit Commitment: the Possible and the Impossible
Bit commitment protocols whose security is based on the laws of quantum
mechanics alone are generally held to be impossible. In this paper we give a
strengthened and explicit proof of this result. We extend its scope to a much
larger variety of protocols, which may have an arbitrary number of rounds, in
which both classical and quantum information is exchanged, and which may
include aborts and resets. Moreover, we do not consider the receiver to be
bound to a fixed "honest" strategy, so that "anonymous state protocols", which
were recently suggested as a possible way to beat the known no-go results are
also covered. We show that any concealing protocol allows the sender to find a
cheating strategy, which is universal in the sense that it works against any
strategy of the receiver. Moreover, if the concealing property holds only
approximately, the cheat goes undetected with a high probability, which we
explicitly estimate. The proof uses an explicit formalization of general two
party protocols, which is applicable to more general situations, and a new
estimate about the continuity of the Stinespring dilation of a general quantum
channel. The result also provides a natural characterization of protocols that
fall outside the standard setting of unlimited available technology, and thus
may allow secure bit commitment. We present a new such protocol whose security,
perhaps surprisingly, relies on decoherence in the receiver's lab.Comment: v1: 26 pages, 4 eps figures. v2: 31 pages, 5 eps figures; replaced
with published version; title changed to comply with puzzling Phys. Rev.
regulations; impossibility proof extended to protocols with infinitely many
rounds or a continuous communication tree; security proof of decoherence
monster protocol expanded; presentation clarifie
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