Yonatan Sompolinsky

Yonatan Sompolinsky is an Israeli computer scientist and blockchain researcher who co-developed the Greedy Heaviest Observed Subtree (GHOST) protocol, which influenced the design of Ethereum. He is known as the founder of Kaspa, a proof of work (PoW) network that uses his Greedy Heaviest Observed Subtree Directed Acyclic Graph (GHOSTDAG) protocol.

Education Sompolinsky graduated from the Hebrew University of Jerusalem with a B.Sc. in mathematics and M.Sc. in computer science. He received his PhD in computer sciences from Hebrew University of Jerusalem in 2021, completing a doctoral dissertation titled "The Design and Architecture of Permissionless Consensus Protocols" under the supervision of Prof. Aviv Zohar. His doctoral research focused on high-throughput blockchain architectures and the ordering of distributed transactions.

Career

Sompolinsky co-founded DAGLabs in 2018, a company dedicated to implementing protocols developed in academia. By 2021, it had closed. He held a postdoctoral research position in computer science at Harvard University's John A. Paulson School of Engineering and Applied Sciences and later became an associate in computer science. His research centered on transaction ordering protocols, distributed consensus, and miner extractable value (MEV).

Research contributions In 2013, as a master's student in computer science at the Hebrew University of Jerusalem, Sompolinsky's research focused on the development of PoW protocols which alleviate the speed-security tradeoff and preserve decentralisation. The development of these protocols then later formed the basis of his PhD. He remains an active contributor to academic and industry research on blockchain and decentralised systems, with an address at the Oxford Union on 12 March 2026. As of April 2026, he has an h-index of 9 according to Google Scholar and his publications have been cited 4,529 times.

GHOST

Sompolinsky’s early research, with Aviv Zohar from 2013-2015 explored limitations of blockchain designs and the security-speed trade‑off of the Nakamoto consensus. They proposed the GHOST protocol as a means to reduce waste from orphaned blocks and improve security in high throughput environments. The protocol was formalised in the academic paper “Secure High-Rate Transaction Processing in Bitcoin” and published in 2015. Vitalik Buterin implemented a simplified single-level version of GHOST in Ethereum's design which was a variant of Sompolinsky's "Inclusive Blockchain Protocols" adapted for proof of stake.

SPECTRE

In 2016, Sompolinsky, Zohar, and Yoad Lewenberg proposed a new protocol dubbed Serialization of Proof-of-work Events: Confirming Transactions via Recursive Elections (SPECTRE). Through this research effort, it was presented as a blockDAG consensus protocol that uses a pairwise ordering of blocks rather than total block ordering to remain secure under high throughput and fast confirmation times.

PHANTOM GHOSTDAG

Following his work on GHOST and SPECTRE consensus protocols, Sompolinsky, together with Zohar in 2021, pursued the idea of a PoW protocol that generalises the Nakamoto consensus to a Directed Acyclic Graph of blocks. They presented a paper titled "PHANTOM GHOSTDAG: A Scalable Generalization of Nakamoto Consensus" which mathematically proves higher throughput without sacrificing security assumptions. This work was featured by ACM Conference on Advances in Financial Technologies and the GHOSTDAG protocol was then implemented as the underlying technology of Kaspa, which achieves a block rate of 10 blocks per second.

DAG KNIGHT

In 2022, Sompolinsky co-authored "DAG KNIGHT: A Parameterless Generalization of Nakamoto Consensus" with Michael Sutton. The paper describes a permissionless consensus protocol that does not assume network latency, remains secure, and is responsive to actual network conditions. It was published through Harvard University's Center for Research on Computation and Society and presented at The Crypto Economics Security Conference (CESC), Berkeley.

Bitcoin From 2013 to 2018, Sompolinsky contributed to research on Bitcoin’s mining behaviour, security properties, and economic incentives. As a speaker at Scaling Bitcoin Hong Kong on December 7, 2015, he shared ideas from this research. He served as Program Chair of Scaling Bitcoin 2019.

In 2015, he researched the economic incentives underlying the mining of Bitcoin. In the paper "Bitcoin Mining Pools: A Cooperative Game Theoretic Analysis", game theory was applied to explain why miners form pools, how cooperative strategies affect network stability, and the role of incentives to maintain consensus. The International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS) published the work in May 2015.

In 2016, Sompolinsky and Zohar examined the security guarantees in "Bitcoin’s Security Model Revisited", which improved the understanding of Bitcoin’s security guarantees and led to working with Ayelet Sapirshtein on extended selfish mining research. They examined adversarial strategies, optimised selfish mining attacks, and identified conditions where miners would have incentive to profitably deviate from the Bitcoin protocol. The work was formalised in "Optimal Selfish Mining Strategies in Bitcoin".

In 2018, Sompolinsky and Zohar completed an analysis on the economic mechanisms that underpin the Bitcoin protocol, which was published in "Bitcoin’s Underlying Incentives". Their work examined Bitcoin's economic incentives for miners such as block rewards and transaction fees.

Development of Kaspa

On 14 August 2021, the domain name kaspa.org was registered, and members of the Kaspa community created a web site at that address. On 2 September 2021, a white paper describing a protocol, titled "PHANTOM GHOSTDAG: A Scalable Generalization of Nakamoto Consensus" was published by the Association for Computing Machinery.

Embedded in the coinbase transaction of the genesis block is the Aramaic text: "Whatever seems good to you and your brothers to do with the rest of the silver and gold, you may do, according to the will of your God.” This note cites Ezra 7:18 from the original Aramaic text Dahava vs. Kaspa. Kaspa is the Aramaic word for “silver” and “money”.

Awards and recognition Sompolinsky was named the winner of the 2025 Binance Blockchain 100 award in the Independent Researcher category. He publicly declined the recognition and an invitation to attend the in-person award ceremony at Binance Blockchain Week on December 3, 2025 in Dubai.

Selected publications

Sompolinsky, Y. and Zohar, A. (2015). "Secure High-Rate Transaction Processing in Bitcoin". Financial Cryptography and Data Security. Sompolinsky, Y., Wyborski, S. and Zohar, A. (2021). "PHANTOM GHOSTDAG: A Scalable Generalization of Nakamoto Consensus". ACM Conference on Advances in Financial Technologies (AFT 2021), pp. 57–70.