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Centralized cryptocurrencies

5 March 2017 Alexander Chepurnoy 6 mins read

Centralized cryptocurrencies - Input Output

Centralized cryptocurrencies

This article is inspired by my recent visit to a blockchain technology conference and my discussions with colleagues about ideas to improve blockchain. Most of the conference speakers were from big Russian banks and their talks were about blockchain use cases, mainly as databases or smart contract platforms. However, none of the speakers were able to answer the question, ‘why…

Authenticated Dynamic Dictionaries, with Applications to Cryptocurrencies

20 February 2017 Alexander Chepurnoy 3 mins read

Our paper "Improving Authenticated Dynamic Dictionaries, with Applications to Cryptocurrencies" will appear at the Financial Cryptography 2017 conference in Malta in April. It was also presented at the Real World Crypto 2017 conference in New York and I highly recommend watching the impressive presentation from Leonid Reyzin, professor of computer science at Boston University…

IODB storage engine

11 October 2016 Alexander Chepurnoy 5 mins read

IODB storage engine - Input Output HongKong

IODB storage engine

Log-Structured-Merge trees (LSMT) are a good fit for modern SSD storage and offer good performance and reliability. LSMT are also a good fit for blockchain storage requirements (snapshots, consistency, proof of existence). This blog post describes a database designed specifically for blockchain storage, inspired by existing LSMT implementations (RocksDB, COLA tree).

The current state-of-the-art LSMT implementation is probably RocksDB, with in-memory write buffers, parallel compaction and snapshots. Another similar algorithm are COLA tree. That is a btree-like structure where each node has separate write buffer. Finally there is SSTable from Cassandra

RollerChain, a Blockchain With Safely Pruneable History

7 September 2016 Alexander Chepurnoy 3 mins read

RollerChain, a Blockchain With Safely Pruneable History - Input Output HongKong

RollerChain, a Blockchain With Safely Pruneable History

When you starting a Bitcoin node it is downloading all the transactions for more than 7 years in order to check them all. People are often asking in the community resources whether it is possible to avoid that. In a more interesting formulation the question would be “can we get fullnode security without going from genesis block”? The question becomes even more important if we…