Tag: bitcoin
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BlockSci: a platform for blockchain science and exploration
The Bitcoin blockchain — currently 140GB and growing — contains a massive amount of data that can give us insights into the Bitcoin ecosystem, including how users, businesses, and miners operate. Today we’re announcing BlockSci, an open-source software tool that enables fast and expressive analysis of Bitcoin’s and many other blockchains, and an accompanying working…
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When the cookie meets the blockchain
Cryptocurrencies are portrayed as a more anonymous and less traceable method of payment than credit cards. So if you shop online and pay with Bitcoin or another cryptocurrency, how much privacy do you have? In a new paper, we show just how little. Websites including shopping sites typically have dozens of third-party trackers per site.…
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Breaking, fixing, and extending zero-knowledge contingent payments
The problem of fair exchange arises often in business transactions — especially when those transactions are conducted anonymously over the internet. Alice would like to buy a widget from Bob, but there’s a circular problem: Alice refuses to pay Bob until she receives the widget whereas Bob refuses to send Alice the widget until he…
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How to buy physical goods using Bitcoin with improved security and privacy
Bitcoin has found success as a decentralized digital currency, but it is only one step toward decentralized digital commerce. Indeed, creating decentralized marketplaces and mechanisms is a nascent and active area of research. In a new paper, we present escrow protocols for cryptocurrencies that bring us closer to decentralized commerce. In any online sale of…
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Bitcoin is unstable without the block reward
With Miles Carlsten, Harry Kalodner, and Matt Weinberg, I have a new paper titled On the instability of Bitcoin without the block reward, which Harry will present at ACM CCS next week. The paper predicts that miner incentives will start to go haywire as Bitcoin rewards shift from block rewards to transaction fees, based on…
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Bitcoin’s history deserves to be better preserved
Much of Bitcoin’s development has happened in the open in a transparent manner through the mailing list and the bitcoin-dev IRC channel. The third-party website BitcoinStats maintains logs of the bitcoin-dev IRC chats. [1] This resource has proved useful is linked to by other sources such as the Bitcoin wiki. When reading a blog post…
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Improving Bitcoin’s Privacy and Scalability with TumbleBit
Last week we unveiled TumbleBit, a new anonymous payments scheme that addresses two major technical challenges faced by Bitcoin today: (1) scaling Bitcoin to meet increasing use, and (2) protecting the privacy of payments made via Bitcoin. Our proof-of-concept source code and a pre-print of the latest version of our paper were both posted online…
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The Princeton Bitcoin textbook is now freely available
The first complete draft of the Princeton Bitcoin textbook is now freely available. We’re very happy with how the book turned out: it’s comprehensive, at over 300 pages, but has a conversational style that keeps it readable. If you’re looking to truly understand how Bitcoin works at a technical level and have a basic familiarity…
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Provisions: how Bitcoin exchanges can prove their solvency
Millions of Bitcoin users store their bitcoins with online exchanges (e.g. Coinbase, Kraken) which store bitcoins on their customers’ behalf. They present an interface that looks somewhat like an online bank, allowing users to log in and request payments to other users or withdrawals. For many users this approach makes a lot more sense than the traditional approach of storing private keys on your laptop or phone…
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“Private blockchain” is just a confusing name for a shared database
Banks and financial institutions seem to be all over the blockchain. It seems they agree with the Bitcoin community that the technology behind Bitcoin can provide an efficient platform for settlement and for issuing digital assets. Curiously, though, they seem to shy away from Bitcoin itself. Instead, they want something they have more control over and doesn’t…