Polygon Zero, the zero-knowledge scaling arm of Polygon, has recently accused developers at Matter Labs of engaging in plagiarism by allegedly copy-pasting a substantial amount of source code from Polygon Zero’s Plonky2 library. The contentious code was found on zkSync, which is a competitor layer-2 scaling solution for Ethereum that also utilizes zero-knowledge technology. Matter Labs is the developer behind the zkSync ecosystem.
Polygon Zero claims that Matter Labs recently introduced a proving system named Boojum, and this system allegedly contains code that was copied from critical components of Polygon Zero’s recursive SNARK Plonky2. A recursive SNARK is a cryptographic proof that enables one party, known as the prover, to demonstrate the truth of a particular statement to another party, known as the verifier, without revealing any additional information.
Polygon Zero asserts that the code was included in Boojum without proper attribution to the original authors or adherence to copyright guidelines. Additionally, Boojum is said to bear striking similarities to Plonky2’s library, employing parallel repetition to enhance soundness in a small field, utilizing similar custom gates to efficiently arithmetize recursive verification, and employing the same lookup argument developed by Polygon Zero’s teammate, Ulrich Haböck.
Polygon Zero claims
The Company further points out that Matter Labs has marketed Boojum as being ten times faster than Plonky2, raising questions about how this is possible when the performance-critical field arithmetic code appears to have been directly copied from Plonky2. In response to this accusation, the Company acknowledges that Matter Labs has given credit for their optimization of the Poseidon parameters, but argues that Boojum takes far more than just the Poseidon constants from Plonky2. They assert that Boojum’s design is nearly identical to Plonky2’s, going so far as to include copy-pasted code.
Plagiarism allegations are not unprecedented in the cryptocurrency community, and similar accusations have arisen in the past. For instance, in March, a member of the Shiba Inu community reported that the Shibarium layer-2 beta testnet and Rinia testnet shared identical chain IDs, leading to claims that the Shibarium alpha testnet was a direct copy of Polygon’s Mumbai testnet.