Albatross: An optimistic consensus algorithm

Abstract – The area of distributed ledgers is a vast and quickly developing landscape. At the heart of most distributed ledgers is their consensus protocol. The consensus protocol describes the way participants in a distributed network interact with each other to obtain and agree on a shared state. While classical consensus Byzantine fault tolerant (BFT) algorithms are designed to work in closed, size-limited networks only, modern distributed ledgers — and blockchains in particular — often focus on open, permissionless networks. In this paper, we present a novel blockchain consensus algorithm, called Albatross, inspired by speculative BFT algorithms. Transactions in Albatross benefit from strong probabilistic finality. We describe the technical specification of Albatross in detail and analyse its security and performance. We conclude that the protocol is secure under regular PBFT security assumptions and has a performance close to the theoretical maximum for single-chain Proof-of-Stake consensus algorithms.

Katal: A standard framework for finance

Abstract – Katal is a new blockchain that provides a standard way to build and deploy decentralized financial applications. It brings together all the components necessary for the backend of a financial application, namely: a high-performance consensus, an authenticated data feed system, a standard for financial contracts and connectivity to the rest of the blockchain ecosystem. Katal enables and simplifies the creation of financial services that are non-custodial, trustless, fast, convenient and interoperable.

Enso: A general-purpose virtual machine

Abstract – In this paper we introduce Enso, a virtual machine designed to be used as general-purpose state transition function in blockchains. This design allows the blockchain application logic to be coded into the state, instead of into the state transition function, making it much more flexible and easier to modify. A byproduct is reducing the frequency of forks, concerted or not.

Deep Ocean: A blockchain-agnostic dark pool protocol

Abstract – We introduce a new cryptographic protocol, called Deep Ocean, that implements a blockchain-agnostic dark pool for cryptocurrencies. Deep Ocean is a layer-two protocol, meaning that it can work with any two cryptocurrencies, as long as there exists an underlying settlement mechanism, for example performing atomic swaps.

Homomorphic Mini-blockchain Scheme

Abstract – We create a new cryptocurrency scheme based on the mini-blockchain scheme and homomorphic commitments. The aim is to improve the mini-blockchain by making it more private. We also make a comparison of Bitcoin and our scheme regarding their ability to resist blockchain analysis.

Privacy and pruning in the Mini-blockchain

Abstract – In order to be useful a cryptocurrency needs to be scalable and private. Despite the dozens of cryptocurrencies launched in the last few years, none tried to solve both these problems. In this paper we improve the mini-blockchain scheme and make it private and even more scalable. We achieve this by encrypting transaction amounts and accounts balances with homomorphic encryption which allows us to perform addition and subtraction on encrypted values without revealing the plaintexts. We also introduce ”expiration dates” on accounts so that users need to pay fees periodically to maintain their accounts. This way abandoned accounts are automatically pruned from the mini-blockchain.