OmniLedger: A secure, scale-out, decentralized ledger via sharding Kokoris-Kogias et al., IEEE S&P 2018 OmniLedger makes a nice complement to Chainspace that we looked at yesterday. The two systems were developed independently at the same time. OmniLedger combines Visa levels of scalability (caution: the authors compare against the average Visa tps, the peak tps in ... Continue Reading

Chainspace: a sharded smart contracts platform Al-Bassam et al., NDSS’18 Chainspace is a DApp (decentralised application) platform based on smart contracts, designed for higher scalability than is currently achievable with Bitcoin or Ethereum. Our modest testbed of 60 cores achieves 350 transactions per second, as compared with a peak rate of less than 7 transactions ... Continue Reading

Blockstack: a global naming and storage system secured by blockchains Ali et al., USENIX ATC’16 We’ll be back in the world of cryptocurrencies and blockchains for the rest of this week, kicking off with this 2016 paper on Blockstack. It’s interesting both for the lessons learned trying to build a system on top of the ... Continue Reading

Bolt: anonymous payment channels for decentralized currencies Green and Miers et al., CCS’17 Yesterday we spent some time looking at what payment channels are, their role in helping Bitcoin to scale by taking some of the load off of the chain, and some payment channels constructions such as direct channels, indirect channels via an intermediary, ... Continue Reading

Bolt: anonymous payment channels for decentralized currencies Green and Miers et al., CCS’17 In which I tried not to rant. But did end up ranting just a little bit... The world of blockchains and cryptocurrencies seems to be growing at quite a pace. Yesterday we looked at Solidus, which provides confidentiality for transactions taking place ... Continue Reading

Solidus: confidential distributed ledger transactions via PVORM Cecchetti et al., CCS’17 Tokens on blockchains can be used to represent assets, and the ledger provides trade settlement on-chain. In a straightforward public blockchain, pseudonyms and transaction values are all publicly visible. Uncovering the true identities behind the pseudonyms becomes a real possibility (‘A fistful of Bitcoins’). ... Continue Reading

Be selfish and avoid dilemmas: fork-after-withholding (FAW) attacks on Bitcoin   Kwon et al., CCS’17 Bitcoin was designed to have no central authority. But power has an amazing way of concentrating. Mining solo is a bit like buying a lottery ticket - big payoff if you happen to win, but your chances of winning are pretty ... Continue Reading

The Ring of Gyges: investigating the future of criminal smart contracts Juels et al, CCS'16 The authors of this paper wrote it out of a concern for the potential abuse of smart contracts for criminal activities. And it does indeed demonstrate a number of ways smart contracts could facilitate crime. It's also though, another good ... Continue Reading