Bitcoin
Bitcoin Rollups Can Boost Transaction Speeds 10x, Developers Say
A team of crypto developers has published a detailed plan to enable transaction rollups on Bitcoin, a common practice in cryptography that was considered impossible on the grandfather blockchain.
Rollups are a decentralized system for pooling off-chain cryptographic transactions before resolving them on-chain in more data-efficient batches, and have historically been used as a scaling solution for Ethereum. The creators of Bitcoin’s proposed structure say the rollups will provide more than increased capacity.
“They bring Turing-complete functionality to Bitcoin,” said Edan Yago, co-author of Bitcoin’s cumulative framework BitSNARK and Graal, in a message to Decrypt. Turing completeness would mean that Bitcoin can use smart contracts, thus enabling decentralized finance (DeFi) and other applications found on other blockchains.
“Initially, we would expect a scale of 10X or more that could maintain the full security of Bitcoin,” he continued. On a separate presentation Earlier this year, the developer claimed that Bitcoin rollup transactions could have infinite scalability in terms of throughput and speed – at least theoretically.
Yago is a contributor to the Bitcoin DeFi platform Sovryn (SOV), which announced the development of its Bitcoin rollup platform Bitcoin OS in January. Unlike other scaling proposals, BitcoinOS does not require soft fork or hard fork upgrades to Bitcoin Core, which evolves deliberately and can be resistant to change.
The whitepaper, published last week, presents two innovations.
One of them is called BitSNARK, a software library for checking zkSNARKS in Bitcoin. zkSNARKS are zero-knowledge cryptographic proofs of completed transactions that do not include or expose any other details.
BitSNARK is a building block of its second innovation, Grail, which is a practical and scalable implementation of BitSNARK to create a cumulative Bitcoin bridge. The Grail Bridge would allow users of the Bitcoin blockchain to move their BTC (and other assets) between layer 2 networks (rollups) in an almost trustless manner.
According to Yago, the design of Bitcoin rollups shares elements of both Ethereum’s ZK rollups and optimistic rollups.
“Bitcoin Rollups are a new beast,” he said. “They will use ZK proofs, but verify them through a challenge/response sequence, similar in some ways to optimistic rollups.”
Moving BTC through BitcoinOS still requires intermediary agents called “operators” to assist in processing bridge deposits and withdrawals. These traders are able to monitor the activity of their fellow traders at all times, preventing any of them from stealing coins from users or processing any type of dishonest bridge transaction.
“As long as a single trader remains honest, the system maintains its integrity,” said Yago.
Yago states that there is also “no theoretical limit to the number of participants” in the pool of decentralized operators. New traders can join and old members can leave by following specific steps. Sovryn says he is working to create a bridge that works efficiently with more than 100 operators.
The proposed rollup system is an outgrowth of Robin Linus’ revolutionary BitVM framework, which introduced the ability to compute anything into Bitcoin last year.
Unlike BitVM, BitSNARK was developed specifically for SNARK verification, the group says, overcoming the practical limitations and inefficiencies of its predecessor in supporting a Bitcoin rollup bridge.
“It offers an order of magnitude improvement in program size and up to a 50% reduction in challenge/response protocol length for the type of computation required by bridges,” the whitepaper states.
Implementing the Grail bridge also solves a problem significant limitation of BitVM bridges called earlier this month. Crypto developer Tyler Whittle claimed that users of such bridges could lose all their funds if bridge operators were forced to process a massive withdrawal that exceeded their available liquidity.
“Grail offers users consistent withdrawal capability,” the white paper says. “The application of a fee market for priority withdrawals, coupled with the ability to scale operators through dynamic opt-in, allows for the smooth and continuous operation of withdrawals.”
Once functional, Yago said Sovryn’s BitcoinOS could render rival L2s and sidechains – such as Liquid, Rootstock and Stacks– “completely obsolete”. While sidechains don’t have the direct security of the Bitcoin network or the decentralized peg of Bitcoin, rollups have both, making them a huge improvement.
In fact, Yago said, the bridge could be so decentralized that no one could compromise it if they tried – not even the government.
“The system is completely designed to defeat attackers at the state level,” Yago said. “A single honest programmer in his basement can successfully defeat a coalition of nation states.”
Edited by Ryan Ozawa.