Robert Linus – project lead at Bitcoin development group ZeroSync – has proposed a new system allowing developers to “compute anything on Bitcoin,” giving it functionality more similar to its neighboring crypto network Ethereum.

Unlike other proposals to expand Bitcoin’s capabilities, “BitVM” does not require any changes to Bitcoin’s code that could cause the network and community to contentiously rift apart.

What is BitVM?

According to the project’s whitepaper published on Monday, BitVM is a “computing paradigm to express Turing complete Bitcoin contracts.”

Rather than executing complex computations on the blockchain itself, the system suggests that they merely be “verified” on Bitcoin, with computation done off-chain. Linus likened the system to optimistic rollups – an Ethereum scaling solution that processes many transactions off-chain before posting them in batches to the main chain.

“This enables more expressive Bitcoin contracts,” explained Linus over Twitter. “Particularly, it enables functionality that we thought we’d need a soft fork for.”

Linus said this could make games like “Chess, Go, or Poker” possible on Bitcoin. He also suggested that it might enable “trustless sidechains” for Bitcoin, meaning BTC could be reliably bridged to other networks without the need for centralization, though this possibility remains uncertain.

The Bitcoin community has hotly debated implementing the “Drivechains” upgrade this year, which would create a system for trustless bridges and blind merge mining on Bitcoin. Theoretically, this could make BTC transactions more private, programmable, and efficient.

However, the risks of implementing and coordinating the upgrade, which would change Bitcoin’s consensus rules, made many skeptical of the proposal. According to Drivechains author Paul Sztorc, Drivechains may become possible via BitVM, though they will be “very inefficient” compared to his own proposal.

Limits of BitVM

Like most proposals, Linus said BitVM still harbors limitations. “The main drawback… is that it is limited to the two-party setting with a prover and a verifier,” he noted, adding that it also requires “significant amounts of off-chain computation and communication… to execute programs.”

Despite generating over 2.4 million impressions on Twitter, many developers were quick to call the project overhyped.

“This is getting way too much attention in Bitcoin world,” said Paradigm researcher Dan Robinson on Monday. “The protocol only works for two parties, so it can’t be used in rollups or other multiparty applications.”

Blockstream CEO and Bitcoin OG Adam Back, also suggested that a different version of Linus’s proposal has existed since 2016, in the form of Greg Maxwell’s Zero-Knowledge Contingent Payment (ZKCP) system.

Linus, however, maintains there are key differences. “You couldn’t play chess in a single ZKCP,” he said.