Liam Eagen, Robin Linus and I published Shielded CSV, the first fully private client-side validation (CSV) protocol, which hides the transaction history.
- The size and verification cost of a coin proof are independent of the transaction history.
- Every transaction costs 64 bytes on-chain, regardless of its size.
- It supports t-of-n accounts and atomic swaps.
Assuming a bridge to Bitcoin, Shielded CSV enables 100 private Bitcoin transactions per second. Compared to private cryptocurrencies, the expensive zero-knowledge proofs never land on-chain and need not be verified by all full nodes. The protocol specification is written in Rust.
It took me a very long time to realize the potential of client-side validation, but I think this may be just the beginning.
Update: I gave a talk about Shielded CSV at the Bitcoin Conference 2025 (slides). This write-up on the btc++ insider is a good introduction as well.