Ben Fisch is a computer scientist specializing in applied cryptography and decentralized systems, known for his research on verifiable computation, zero-knowledge proofs, and blockchain protocols. He is a co-founder, CEO, and CTO of Espresso Systems and an assistant professor of computer science at Yale University. ^[1]

Education

Fisch graduated from the University of Pennsylvania in 2013 with a Bachelor’s degree in Mathematics, Logic, Information, and Computation. He continued his studies at Stanford University, where he earned a PhD in Computer Science in 2021, concentrating on applied cryptography and decentralized systems. ^[2]

Career

Fisch began his career with several research-focused roles. He was a summer research student at the Weizmann Institute of Science from 2012 to 2013. He later worked at Columbia University’s Cryptography Laboratory between 2013 and 2014, where he contributed to projects on secure search systems. Following this, he spent just over a year as a software developer at the data analytics firm 1010data before commencing his doctoral studies at Stanford University in 2015.

During his PhD program, Fisch's research centered on privacy and verifiability within information systems, leading to the development of novel cryptographic methods that have had a significant impact on the blockchain industry. His work from this period introduced foundational concepts for several major protocols. While pursuing his doctorate, he also took on advisory roles for prominent projects in the decentralized technology space. He began advising Chia Network in 2017 and Protocol Labs, the organization behind Filecoin, in 2018. He also served as an advisor to Eco from 2018 to 2020.

In 2020, Fisch co-founded Espresso Systems, a company that develops infrastructure to address scalability and interoperability challenges in the blockchain ecosystem, where he serves as CEO and CTO. In 2022, he joined the faculty at Yale University as an assistant professor of computer science, a position he holds concurrently with his leadership role at Espresso Systems, allowing him to continue his academic research while directing industry-focused projects. ^{[3] [4]}

Interviews

Espresso

During a November 2024 interview with Genzio, Fisch introduced Espresso, a solution designed to address the composability problem in Web3 environments characterized by multiple blockchain ecosystems. He noted that the evolution of many chains, particularly within Ethereum, has led to fragmentation that undermines the core principle of interoperability in Web3. Espresso originated from Fisch's experience while developing a privacy protocol, prompting a pivot to focus on facilitating interaction across different chains while maintaining scalability. Established towards the end of 2020, Espresso seeks to provide a global confirmation layer for seamless chain interaction. Fisch emphasized the importance of maintaining a unified composable system in Web3 to support broader industry adoption, suggesting that infrastructure decisions must be made collaboratively to ensure compatibility among various layers. As Espresso prepares to integrate live rollups, Fisch expressed excitement about the potential for enhanced security and composability within the ecosystem as it moves beyond test phases toward production. ^[5]

Presentations

Fast Confirmation Layer

In a presentation on composability in Web3 applications at ETHDenver in February 2025, Fisch emphasized that effective communication between applications relies on a fast confirmation layer, noting the importance of low latency for real-time interactions. He discussed the challenges of interchain messaging, which can introduce new trust assumptions when applications on different chains interact, such as the need for one chain to trust the finality of another. Fisch explained that intra-chain messaging allows for zero relative latency and does not require new trust assumptions, whereas interchain messaging necessitates trusting external sources. He highlighted the advantages of Layer 2 (L2) applications with their ability to achieve rapid confirmation through sequencers, albeit with associated risks of hacking. To mitigate these risks, he proposed using a separate consensus protocol that provides a layer of security beyond direct trust in the sequencer, thereby enhancing the integrity of confirmations across chains. ^[6]

CIRC

At BASSLite Devcon in February 2025, Fisch discussed a coordinated inter-communication protocol referred to as CIRC, outlining its potential to enable synchronous composition in decentralized applications. He emphasized the importance of composability in Web3, contrasting it with Web2's asynchronous interactions that typically require trust in operators. Fisch highlighted the emergence of a multi-chain environment built atop Ethereum, which allows independent applications to act as building blocks for one another. He explained the challenges of maintaining composability across different blockchains, particularly regarding transaction atomicity and the need for effective cross-chain messaging. Fisch presented solutions involving shared assets and optimistic rollups to enhance the efficiency of cross-chain communication. He concluded by proposing an approach based on coordinated execution of transactions across multiple rollups to achieve synchronous composability, which was outlined in a short paper he co-authored. ^[9]

Beyond Base Layer

At ETHDenver in March 2024, Fisch discussed Espresso, a marketplace concept for ad-hoc shared sequencing on Ethereum rollups. He explained that traditional rollups operate with isolated sequencers, which limit interoperability among applications, resulting in liquidity fragmentation. Fisch emphasized the potential of a shared sequencer model where rollups can both manage their own transactions and sell sequencing rights to others, thereby enhancing connectivity and reducing user costs. The presentation also highlighted the importance of layered architecture, outlining how base sequencing could improve communication between different rollups while maintaining decentralization. Additionally, Fisch proposed a shared sequencing auction system that allows rollups to participate dynamically, maximizing revenue while preventing isolation. The overarching goal was to promote interoperability across Ethereum applications, ensuring a seamless user experience. ^[8]

Decentralized Sequencing

During Rollups-as-a-Service Day (RaaS Day) in June 2023, Fisch discussed the concept of Espresso and a decentralized sequencing layer for rollups. He highlighted how rollups enable horizontal scaling in blockchain networks by allowing applications that cannot run directly on Layer 1 to operate independently, thereby reducing the workload on the Layer 1 nodes. Fisch pointed out the current centralization issues within rollup servers, which control transaction inclusion and generate concerns around censorship and monopolistic practices. He proposed that separating transaction ordering from execution could restore some decentralized properties by allowing users to submit transactions directly to a consensus network for ordering, while application-specific servers would handle execution. He also outlined how a shared sequencing layer could improve interoperability between different rollups and mitigate systemic security risks associated with bridges. Fisch concluded by raising open questions regarding revenue sharing and mechanism independence in shared sequencing layers as challenges yet to be addressed in the evolving rollup ecosystem. ^[7]

Panels

Sequencing Day

The "Sequencing Day Surprise Panel" hosted during Sequencing Day in December 2024 featured discussions among Fisch (Espresso), Amir Forouzani (Puffer), and AJ Park (Radius), focusing on the evolution and implementation of execution tickets in their respective blockchain projects. The panelists shared their experiences and motivations for pivoting from earlier concepts to execution tickets, which they believed enhanced user accountability and expertise. They emphasized the importance of decentralized sequencing, shared composability, and the complexities surrounding marketplace solutions for sequencing rights. The discussion also touched on the challenges of establishing a strong infrastructure versus user-facing applications in the blockchain space, concluding on a positive note with optimism for future developments and community engagement in these ongoing discussions. ^[10]