The History of Bitcoin Sidechains | with Rootstock creator Sergio Lerner
Bitcoin Rails | Isabel Foxen DukeShow Notes
The ultimate Bitcoin "scaling OG,” Sergio Lerner, has been working on Bitcoin bridges since 2012. Sergio was the first person on the Bitcoin Talk forum to propose the idea that “one chain could validate the consensus of another chain,” and architected the first functioning Bitcoin sidechain, Rootstock, shortly after the canonical Blockstream sidechains paper was published in 2014.
Lesser known is Lerner’s recent contributions to the development of BitVM—through his team’s Alliance-independent implementation, BitVMX. In addition to their unique BitVM implementation (optimizing for different tradeoffs compared to Robin Linus BitVM Alliance), the BitVMX team is quietly operating as the “fixer” service provider to many of the most interesting BitVM rollups set to launch in 2026.
In this episode, Lerner and I dive deep into the history of Bitcoin sidechains, why various projects of the past decade have succeeded or failed (and the legacies they left behind), and the trust-minimized future he sees through the development of BitVM/BitVMX.
This episode of Bitcoin Rails is powered by:
— Best In Slot — the leading API for Ordinals and BRC-20 data aggregation and indexing.
— Spark — a statechains implementation advancing Bitcoin-powered payments.
— Citrea — a leading Bitcoin rollup technology and BitVM alliance contributor.
📌 TIMESTAMPS
00:00 Intro
01:39 Early Bitcoin and Cryptography Background
03:55 Bitcoin’s Limits Back in 2012
05:26 The First Turing-Complete Cryptocurrency
06:27 Contributions to Bitcoin and Ethereum
16:52 Why Mining Centralization Is Bitcoin’s Biggest Risk
24:34 Rootstock vs. Original Sidechains Whitepaper
33:50 Federated Bridges and Their Trade-offs
40:49 First Rootstock Users
46:31 Merge Mining and Bitcoin Security
56:03 Fairgate, BitVM, and Garbled Circuits
01:06:37 Bridging Models and Business Constraints
More from Bitcoin Rails | Isabel Foxen Duke
There are few people as close to the frontlines of Bitcoin privacy as Cake Wallet COO Seth for Privacy. After cutting his teeth building for Monero, Seth turned his focus to Bitcoin in 2022, with the view that making Bitcoin more private would ultimately help more people than focusing on a smaller niche target group alone.
Isabel Foxen Duke sits down with [[alloc] init] co-founder Misha Komarov and Head of Protocol Research Clara Shikhelman to examine PIPEs, a cryptographic framework that utilizes witness encryption—a primitive long dismissed as purely theoretical—to unlock advanced Bitcoin programming without a soft fork.
The first fully specified post-quantum signature scheme for Bitcoin has been proposed to the Bitcoin mailing list.
To date, post-quantum Bitcoin discussions have largely centered on which digital signature schemes offer the strongest cryptographic security against a quantum adversary.
Paul Sztorc founder and CEO of LayerTwo Labs and author of Bitcoin Improvement Proposals 300 and 301 (Drivechains), has been one of Bitcoin's most persistent—and controversial—thinkers, advocating for merge-mined sidechains as a way to dramatically expand Bitcoin's functionality while preserving the security of the base layer.