495 research outputs found
Systematizing Decentralization and Privacy: Lessons from 15 Years of Research and Deployments
Decentralized systems are a subset of distributed systems where multiple
authorities control different components and no authority is fully trusted by
all. This implies that any component in a decentralized system is potentially
adversarial. We revise fifteen years of research on decentralization and
privacy, and provide an overview of key systems, as well as key insights for
designers of future systems. We show that decentralized designs can enhance
privacy, integrity, and availability but also require careful trade-offs in
terms of system complexity, properties provided, and degree of
decentralization. These trade-offs need to be understood and navigated by
designers. We argue that a combination of insights from cryptography,
distributed systems, and mechanism design, aligned with the development of
adequate incentives, are necessary to build scalable and successful
privacy-preserving decentralized systems
Bitcoin over Tor isn't a good idea
Bitcoin is a decentralized P2P digital currency in which coins are generated
by a distributed set of miners and transaction are broadcasted via a
peer-to-peer network. While Bitcoin provides some level of anonymity (or rather
pseudonymity) by encouraging the users to have any number of random-looking
Bitcoin addresses, recent research shows that this level of anonymity is rather
low. This encourages users to connect to the Bitcoin network through
anonymizers like Tor and motivates development of default Tor functionality for
popular mobile SPV clients. In this paper we show that combining Tor and
Bitcoin creates an attack vector for the deterministic and stealthy
man-in-the-middle attacks. A low-resource attacker can gain full control of
information flows between all users who chose to use Bitcoin over Tor. In
particular the attacker can link together user's transactions regardless of
pseudonyms used, control which Bitcoin blocks and transactions are relayed to
the user and can \ delay or discard user's transactions and blocks. In
collusion with a powerful miner double-spending attacks become possible and a
totally virtual Bitcoin reality can be created for such set of users. Moreover,
we show how an attacker can fingerprint users and then recognize them and learn
their IP address when they decide to connect to the Bitcoin network directly.Comment: 11 pages, 4 figures, 4 table
An Analysis and Enumeration of the Blockchain and Future Implications
The blockchain is a relatively new technology that has grown in interest and potential research since its inception. Blockchain technology is dominated by cryptocurrency in terms of usage. Research conducted in the past few years, however, reveals blockchain has the potential to revolutionize several different industries. The blockchain consists of three major technologies: a peer-to-peer network, a distributed database, and asymmetrically encrypted transactions. The peer-to-peer network enables a decentralized, consensus-based network structure where various nodes contribute to the overall network performance. A distributed database adds additional security and immutability to the network. The process of cryptographically securing individual transactions forms a core service of the blockchain and enables semi-anonymous user network presence
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