Part 3: Dr. Sompolinsky's background introduction


Dr. Yonatan Sompolinsky, the pioneer of PoW BlogDAG

Yonatan's works have been appearing in academic papers since 2014, mentioned or recognized across the technological and academic spheres.

  • Citation results provided by Google (Scored 3329)

His main focus, however, remained aimed at working on his thesis, which improved with every protocol he helped bring to existence.

To have an overview of all protocols Yonatan was involved in as the author and co-author, read the Exploring Yonatan Sompolinsky's blockDAG Protocols | HackerNoon article.

Yonatan's focus timeline:

  • The Academic and Bitcoin involvement between 2014 and now.

  • As a graduate computer science student at Hebrew University in 2014, Yonatan started a lab project with today's Professor Aviv Zohar.

  • The specific effort to implement POW DAG in real-world applications was between 2018 and 2021, and 2018 is also the year Yonatan joined the crypto space and started DAGlabs.

After completing his undergrad studies in mathematics, Yonatan joined the computer science grad program and joined Professor Aviv Zohar's lab. The main thesis question put forth by his advisor Aviv was around latency in Bitcoin and Bitcoin-like systems and the implications of latency barriers on security, throughput, fairness, and more.

This was really early in the Bitcoin era when almost no academic papers regarding Bitcoin had been released, with the notable exception of the "On Bitcoin and Red Balloons" paper by Professor Zohar and his colleagues.

As a challenge, his advisor asked him to work on the question of lowering the latency in Bitcoin block creation to under 10 minutes. This limit was originally proposed by Satoshi Nakamoto so that the network would have time to propagate the latest block, and reducing the limit could cause significant security vulnerabilities.

  • Many large decentralized systems rely on information propagation to ensure their proper function.

  • Bitcoin relies on a peer-to-peer network to track blocks (=batches of transactions) that are performed with the currency. For this purpose, every new block a node learns about should be transmitted to its neighbors in the network.

  • The block creation rate in Bitcoin must be suppressed in order to ensure that the block interval is much smaller than the worst-case latency in the network.

"The question of latency assumptions sits at the core of any consensus system. Regardless of designing a permission or a permissionless consensus system, you want to know how many and how fast messages can accelerate and what happens if you try to make it work at internet speed." - Yonatan Sompolinsky.

Initially, these questions may seem straightforward, but upon closer examination, numerous subtle nuances had to be carefully considered. Yonatan embarked on a journey to address these nuanced inquiries, which ultimately led to the publication of the GHOST protocol, marking the first significant milestone in his research.

By the time Buterin mentioned GHOST in the Ethereum whitepaper, Aviv and Yonatan were already working on the blockDAG paradigm, the next step of enhancing Nakamoto Consensus by embedding blocks in a full graph form (DAG) rather than a tree (as in Bitocin and GHOST). This way, they created a new paradigm in which they needed to solve and prove many minute details and answer questions that needed thorough research first. The outcomes of working on this paradigm were published as the Inclusive Blockchain Protocols paper and then the SPECTER protocol, another perhaps lesser-known DAG protocol.

Yonatan was then invited to join the Satoshi roundtable to meet several industry leaders, where he figured out that the academic proof for SPECTRE should not be the focus of his post-academic career. At the roundtable, Yoanatan discussed the need for a solution to implement his work into a stand-alone PoW platform. To make this idea a reality, he co-founded an RnD entity called DAGlabs.

This was followed by the release of another iteration of a blockDAG consensus paper, the Phantom paradigm, based on the greedy variant of which the GHOSTDAG consensus was created.

Phantom-Ghostdag, or just GHOSTDAG, is an inclusive consensus protocol that should fulfill the DAGlabs goal of applying Yonatan's work to a PoW project.

A little bit later, DAGlabs members realized that for a PoW project to succeed, it was crucial to avoid centralization created by DAGlabs and ensure the community's growth in an organic manner. Instead of a project backed by a centralized entity, they rather decided on an open-source crypto community. They took the already implemented GHOSTDAG code and launched the Kaspa mainnet.

Kaspa's fair launch created equal conditions for all participants, including:

  1. No pre-mine: Kaspa had no pre-mined coins, meaning the initial supply was not allocated to specific individuals or entities before the project's launch. This helped prevent any concentration of wealth or control in the hands of a select few.

  2. No rewards for founders: The founders of Kaspa did not receive any special rewards or incentives beyond what was available to other miners. This further reinforced the idea of equal conditions and avoided potential distortions in the early stages of the project.

  3. Equal conditions for all initial miners: Every participant in the initial mining phase had the same opportunities and faced the same conditions. This approach encouraged broad participation and ensured a more decentralized mining power distribution.

  4. The Polychain VC investment funded the DAGLabs development, with only a small portion allocated to mining. DAGlabs mined approximately 800MKas (3% of the fully diluted supply). Half of the mined coins were distributed to investors, while the other half was divided among DAGlab's former employees.

  5. The community voted on the mining algorithm one day before the network launched.
    The mining algorithm was also modified to prevent existing GPU/FPGA miners from mining it, allowing CPU mining during the first few weeks.

  6. The fair launch allowed many people to CPU mine Kaspa from the start.

The rapid emission schedule ensured that most of the coin was already in circulation when the network became ASIC dominant. Till then, the coin was mostly mined by GPU/FPGA miners, who have far more operational expenses and thus sold more of their yield to the market and increased the circulation supply.

By adhering to these fair launch points, Kaspa sought to establish a PoW economy that responded to natural market dynamics, where mining and demand would be driven by the actions and choices of the community as a whole. This approach aimed to foster a robust decentralized network while promoting a fair and inclusive ecosystem.

DAGlabs was dissolved so that nothing stood in Kaspa's way, and Yonatan moved to Harvard as a postdoc. During that time, he worked with Michael Sutton, a core researcher, current tech lead, and developer in the Kaspa community, on the pinnacle of his blockDAG research line, the DAGKnight protocol, authored by Michael Sutton under Yonatan's guidance.

The goal of the Kaspa core contributors now, besides finalizing the RUST rewrite of Kaspa nodes and increasing blocks per second (BPS) cardinality to 30, is to apply the DAGKNIGHT protocol as the new Kaspa consensus protocol, which combines the best of all the previous protocols as an ultimate solution for the PoW's overall performance.

Dr. Yonatan Sompolinsky, the academic

Yonatan's journey to the limelight of technological innovation started at the Hebrew University of Jerusalem, where he studied mathematics as an undergraduate and continued with computer science in grad school.

There, he met Aviv Zohar, his future advisor. Together, they started a lab project, the results of which were formalized in an academic paper called Secure High-Rate Transaction Processing in Bitcoin, which contained the GHOST protocol - an alternative to Bitcoin's longest chain rule.

  • GHOST utilizes the proof of work embedded in orphan blocks by traversing the tree structure (resulting from forks under high speed) and selecting the main chain differently.

Back then, still, as a mathematician, Yonatan was most intrigued with the aspect of probability theory in the work he was doing with Prof. Zohar. However, in the final form of the GHOST paper, this aspect was relegated only to its appendix.

What started as a theoretician's interest later became a full-blown pursuit of the mysteries of crypto - a pursuit that he maintains to this day.

Around the beginning of 2018, Yonatan co-founded the research and development (RnD) project called DAGlabs (2018-2021), the mission of which was to commercialize the DAG protocols. DAGlabs was seed-funded by Polychain and other VCs and slowly turned from a University project to a startup.

At the same time, Dr. Sompolinsky continues his academic career as a Computer Science postdoc at Harvard University, researching transaction ordering incentives and dynamics.

The complete summary of Dr. Sompolinksy's DAG research line will be published in a separate article.

Until next time!