Toby Sharp joined Brink engineers to present Hornet, an executable specification for Bitcoin consensus.
In his presentation, he discussed:
- “The code is the spec”
- How Hornet differs from libbitcoinkernel
- Properties of a good specification
- The 35 semantic rules that define block validity
- A declarative C++ implementation of the rules
- A custom UTXO database designed for Bitcoin
- Approaches to block validation
- Ideas of a domain specific language (DSL) for consensus
- Differential and adversarial testing
- Q&A with the audience
This discussion was recorded on June 12, 2026.
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