Cryptography and Cryptocurrencies
Bulletproofs: Short Proofs for Confidential Transactions and More (Unpublished)
TLDR: Confidential transactions are bitcoin transactions which are publicly verifiable but do not reveal the amounts that are transferred. They rely on cryptographic commitments and so called zero-knowledge proofs of knowledge. We present a new kind of zero-knowledge proof which is much more efficient and can be used to drastically reduce the size of confidential transactions. On a more technical note bulletproofs are non-interactive zero knowledge proofs without trusted setup and with only logarithmic proof size. Proving and verification cost are linear with low constant overhead.
Provisions: Privacy-preserving proofs of solvency for Bitcoin exchanges
Published at CCS 2015
TLDR: How can a Bitcoin exchange proof that they have enough funds to satisfy all their customers demands without revealing the customers balances, the bitcoin addresses they control or even the total amount of bitcoin they have.
Proofs-of-delay and randomness beacons in Ethereum
Presented at IEEE S&B Workshop
TLDR: We show how one can generate an unpredictable randomness beacon that is publicly verifiable using a blockchain. The beacon can be used to verify the correct execution of randomized algorithms such as lotteries. The novel property of the beacon is that it is publicly verifiable in that a verifier is convinced that the beacon was unpredictable even if she did not partake in the generation of the beacon and without any trust assumptions. We also show how we can enable interactive verification using an efficient smart contract.
Game Theory (Combinatorial Auctions)
A Faster Core Constraint Generation Algorithm for Combinatorial Auctions
Published at AAAI 2015
TLDR: We significantly improve on the current state of the art algorithm for computing combinatorial auctions. These auctions were multiple related goods are sold in the same auction are for example used to allocated spectrum to cellular companies around the world. These auctions often generate billions of dollars in revenue but are often limited to a small number of bidders and goods. Faster algorithms for computing their outcome will enable larger scale applications.
Computing Bayes-Nash Equilibria in Combinatorial Auctions with Continuous Value and Action Spaces
Published at IJCAI 2017
LLG BNEs (Working Paper)
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