Polygon Zero accuses Matter Labs’ developers of plagiarism

Polygon Zero has accused Matter Labs of copying significant code from its Plonky2 library to zkSync, a rival Ethereum layer-2 scaling solution.

Update (Aug. 3 at  9:49 p.m. UTC): This article has been updated to add Matter Labs' response. 

Polygon’s zero-knowledge scaling arm, Polygon Zero, is accusing developers of Matter Labs of copy-pasting “a substantial amount of source code” from its Plonky2 library, according to an announcement on Aug. 3.

The allegedly plagiarized code was found on zkSync, a competitor layer-2 scaling solution for Ethereum powered by zero-knowledge technology. Matter Labs, the developer of the zkSync ecosystem, has denied the claims.

According to Polygon Zero, Matter Labs recently released a proving system called Boojum with lots of code copy-pasted from critical components of its recursive SNARK Plonky2. A recursive SNARK is a cryptographic proof that allows one party (the prover) to demonstrate to another party (the verifier) that a certain statement is true, without revealing any additional information.

Crypto runs on the open source ethos. When projects don’t follow it, the ecosystem suffers.

We were disappointed to see that @zksync copied our code without attribution and made misleading claims about the original work, so we wrote this post.
https://t.co/8VnoYVWgI8

— Polygon Zero (@0xPolygonZero) August 3, 2023

Polygon Zero claims that the code was included without the original copyrights or clear attribution to the original authors. It also noted that Boojum is extremely similar to Plonky2’s library. “It uses the same strategy of parallel repetition to boost soundness in a small field, similar custom gates to efficiently arithmetize recursive verification, and the same lookup argument developed by our teammate Ulrich Haböck," reads the blog post.

Furthermore, Polygon noted that Matter Labs has marketed Boojum as 10x faster than Plonky2. “Wondering how this is possible, given that the performance-critical field arithmetic code is directly copied from Plonky2?”

According to Polygon Zero:

“It’s great to give credit, and we appreciate the recognition for our optimization of the Poseidon parameters. However, it might not be apparent to the reader that Boojum borrows far more than the Poseidon constants from Plonky2, and in fact that Boojum’s design is nearly identical to Plonky2’s, even to the point of copy-pasted code."

In comments to Cointelegraph, Matter Labs expressed disappointment to see Polygon’s leadership team "spreading untrue claims." According to a spokesperson, "the new Boojum high-performance proof system leverages 5% of from Plonky2, which is prominently attributed in the first line of our module. Where else, other than the very first line of our library would this have been included if we wanted it to be more prominent?"

While we're writing a detailed response, consider the very first line of the main file of this module:https://t.co/6PHa9mcrba https://t.co/Vw726Qp6Nh

— Alex G. ∎ (@gluk64) August 3, 2023

This isn’t the first time plagiarism accusations have surfaced in the crypto community. In March, a member of the Shiba Inu (SHIB) community reported that the Shibarium layer-2 beta testnet and Rinia testnet had identical chain IDs, along with claims that the Shibarium alpha testnet was a copy of Polygon’s Mumbai testnet.

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