StarkWare Brings Zero-Knowledge Tech to Bitcoin, Verifying zk-Proofs on Signet Testnet

The mechanism, which took three months to complete, was implemented on Bitcoin's testnet Signet, and still has a long way to go before it can be used in the broader ecosystem.

StarkWare, a company developing zero-knowledge technology on Ethereum since 2018, has successfully verified a zero-knowledge proof (ZK-proof) in a Bitcoin testnet.

The mechanism, which took three months to complete, was implemented on Bitcoin’s testnet Signet. However, it still has a long way to go before it can be used in the broader ecosystem.

The script that enables something like zk-proofs (OP_CAT) still hasn’t received enough consensus in the Bitcoin community for it to be introduced.

Despite this setback, StarkWare’s move is an auspicious one for the network formerly known as a digital pet rock.

Verifying zk-proofs on Bitcoin was previously unavailable, due to the network’s limited computational capabilities. OP_CAT, and the companies battle testing it on Bitcoin’s Signet, aims to change that reality and bring the breadth of applications present on other blockchains to the oldest ecosystem in the industry.

“This was a tremendous effort and took a significant amount of time,” said Weikeng Chen, of L2 Iterative in a statement shared with The Defiant. “We started with nothing. There’s no information about ZK proofs on Bitcoin. There’s no information regarding the mathematical operations to follow. We had to build the full stack, which eventually led to the implementation of the STARK verifier.”

A zk-proof occurs when one party can prove to another that a given statement is true without revealing any additional information. Zk-proofs have become one of Ethereum’s most valuable computational tools, especially as the race to scale in a privacy-centric manner continues.

Ethereum’s Rollup Race Comes To Bitcoin

There are two types of rollups on Ethereum: optimistic and zero-knowledge.

Optimistic rollups assume all Layer 2 transactions are valid unless challenged and proven wrong by an honest network validator, whereas zk-rollups assume all transactions are false until proven valid through zk-proofs.

According to L2Beat, optimistic roll ups like Arbitrum, Base, and Optimism command nearly 70% of the entire market share. Trailing from afar with 1.7% of the total market is StarkWare’s own Layer 2, Starknet, which lands in fourth place in its category behind Linea (2.9%), ZKSync (2.8%), and Scroll (4.3%), which has had its total value locked (TVL) soar past $1 billion.

However, even though zero-technology scaling solutions are less widely used, they have important advantages including increased privacy and faster bridging times to mainnet.

Privacy is where StarkWare has been placing its efforts, in no small part due to its founder and Chief Executive Officer Eli Ben-Sasson’s connection to the privacy blockchain world. Ben-Sasson was the chief scientist behind one of the top privacy-focused cryptocurrencies: Zcash.

Zcash has lost dominance in its sector and shows a $478 million market cap, down from its $3.5 billion peak in 2022. The token spiked 8% to $31 today, for reasons that seem unclear.

Testing out zero-knowledge technology makes sense on Bitcoin because of its well-known lack of privacy and difficulty to scale.

OP_CAT Continues To Get Tested

The potential to bring some of Ethereum’s most valued tools to Bitcoin is enabled by a Satoshi-era code dubbed OP_CAT.

OP_CAT, short of “Operation Concatenate,” is an opcode that was proposed originally by Bitcoin’s unknown creator, Satoshi Nakamoto. It allows for the combination of two pieces of data into a single piece of data during the execution of a Bitcoin transaction.

The opcode is nothing short of controversial.

Many in the Bitcoin community have decried it as an attack on the network, which could open up attack vectors like MEV. In fact, MEV-style attacks known as ‘mempool sniping’ have become prevalent, although it is mostly due to Ordinals and not OP_CAT.

Ben-Sasson and StarkWare are on the front line testing and pushing for OP_CAT to be reintroduced. In early June, the company revealed an ambitious plan to scale Bitcoin through the controversial script–and the zk-proof is a step in that direction.

Referring to OP-CAT, Ben-Sasson said “it will retain all Bitcoin values unchanged, while providing a bare bones framework that is just enough to bring STARK scaling to Bitcoin.”