Before Blockchains, There Was State Machine Replication

July 14, 2026

1:06

Before Blockchains, There Was State Machine Replication

Imagine a system that keeps your data consistent across dozens of servers — long before Bitcoin even existed. That’s where state machine replication comes in, developed way back in the 1980s by researchers like Barbara Liskov, who’s featured in a16z’s conversation with Tim Roughgarden. ((slower)) These ideas weren’t about cryptocurrencies, but about making distributed systems reliable despite failures or malicious actors. According to Liskov, the core insight is that you can ensure all copies of a system stay in sync if they follow the same rules — no matter what happens. ((upbeat)) What’s fascinating is how these foundational concepts — like viewstamped replication and PBFT — are still at the heart of blockchain protocols today, as explained by content+a16zpodcast@a16z.com. Now, here’s where it gets interesting — these theories are evolving alongside AI, creating a whole new wave of system design. That shift might seem subtle now, but it’s exactly the kind of signal that sparks the next big leap.

Every blockchain today relies on replication techniques first developed in the 1980s by researchers who weren't thinking about cryptocurrencies at all.

In this episode, Tim Roughgarden speaks with MIT professor and Turing Award winner Barbara Liskov, one of the pioneers of programming languages, fault tolerance, and distributed systems. Joined by a16z crypto research partner Ittai Abraham, they trace the evolution of ideas that now underpin modern blockchain networks.

The conversation explores viewstamped replication, Practical Byzantine Fault Tolerance (PBFT), state machine replication, and why concepts developed decades before Bitcoin became the foundation for today's blockchain protocols. Along the way, Liskov reflects on the relationship between theory and practice, the importance of modularity and formal reasoning, and why AI is creating a new generation of systems research.

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Audio Transcript