Rarimo’s July Highlights

6 min readAug 17, 2023


Spearheading the World’s First Multi-Chain ZK Proofs for Verified Credentials: Rarimo and Polygon ID’s collaboration

In a revolutionary step forward for on-chain identities, Rarimo collaborated with Polygon ID, the Privacy Preserving ID infrastructure, to make their credentials multi-chain. At a single swoop, each and every identity provider using Polygon ID became instantly cross-chain.

Not only is this the first time ever that Polygon ID has become multi-chain but as PolygonID is the first and only solution that allows users to represent off-chain credentials as Zero-Knowledge Proofs (ZKPs), the collaboration also marks a world first for the digital identity space.

Before its Rarimo collaboration, Polygon ID’s credentials could only be used on the chain where they were originally issued. This meant that if you issued your credential on Polygon, you would not be able to use it on Ethereum. Instead, you would have to issue a new, Ethereum-native credential. Now, however, credentials issued on Polygon can be used seamlessly on Ethereum. In the coming weeks, they will also become available on BNB Chain and Avalanche, and as the number of networks that Rarimo can scale to is limitless, a range of additional chains will be added with time.

Rarimo celebrated the Polygon ID collaboration by demoing at Polygon ID’s DevX event at this year’s Ethereum Community Conference (EthCC) in Paris.

An Inception Moment: The Future of Web3 and the Role of Digital Identities

Rarimo is particularly excited about the collaboration because it provides an early glimpse into the future of Web3. Demand for robust on-chain identity is mounting from both within the Web3 space and outside of it. Inside Web3, many of the space’s most exciting emerging innovations such as on-chain games and decentralized social media require some form of on-chain identity, and outside, the need for more robust online credentials has grown urgent in the face of AI.

Ensuring that identity credentials are multi-chain is essential to their robustness. Without the freedom to move identity credentials across dApps and ecosystems, users cannot be said to truly own their digital identities and are instead forced to contend with the same threat of walled gardens that plagued Web2. By making Polygon ID’s ZKP’s multi-chain, Rarimo is delighted to have helped set a precedent for such interoperability.

You can read more about the collaboration in this Blockworks article or here on our blog, and watch the demo here on Polygon ID’s YouTube Channel

(Note: you can learn more about the demand for robust identity solutions in our below summary of Vitalik’s Proof-of-Humanity blog post.)

ZK-Proofs at Eth-CC

Rarimo’s and Polygon ID’s collaboration was not the only talk or demo at EthCC to make use of innovations in Zero-Knowledge (ZK) technology. In fact, one of the most exciting aspects of this year’s conference was that so many events were focused on ZK innovation.

What is Zero-Knowledge Cryptography?

Zero-knowledge cryptography is critical to the evolution of the digital identity space. It enables one party to prove to another that a certain statement is true, without revealing any additional information. This is invaluable to the preservation of user privacy. A user could, for instance, prove that they are over eighteen, without revealing their exact date of birth.

Zero-Knowledge Machine Learning

One of the talks that Rarimo community members found particularly inspiring was Zero-Knowledge Machine Learning (ZKML) and its use cases by DcBuilder, a research engineer at Worldcoin. DcBuilder outlined how ZK proofs can be used to improve the transparency of AI, and facilitate its integration with blockchain technology. Just one of many use cases DcBuilder covered included leveraging ZKPs to provide guarantees that the machine learning model being run behind an API truly is the one we’ve been told it is. For instance, you might want assurances that OpenAI is providing you with outputs from GPT-4 rather than GPT 3.5. Given the intrinsically opaque nature of ever-evolving machine learning algorithms, such applications would be revolutionary.

ZKML not only represents the cutting edge of Zero Knowledge research, but reflects Rarimo’s belief in blockchain technology as a solution to many of the challenges posed by AI. You can read more about Rarimo’s thoughts on how AI can benefit from blockchain in last month’s newsletter.

Blockster Coverage: Rarify Labs on ZK’s at EthCC

Co-founder of Rarimo service-provider Rarify Labs, Lasha Antadze’s observations on ZK prevalence at EthCC was quoted in Blockster:

“Conferences always provide a glimpse into the upcoming movements sweeping Web3. This year, we noticed a focus on zero-knowledge technologies. This was particularly exciting for us, as builders with a focus on digital identities, because zero-knowledge proofs allow users to confirm specific aspects of their identity without compromising their privacy.

We’re looking forward to seeing how the innovations discussed during the conference are implemented over the next year and we expect to see an explosion of social identity-focused use cases.”

Proof-of-Humanity — An Upcoming Use Case and Vitalik’s blog

On the 24th of July, Ethereum co-founder Vitalik Buterin published a blog titled ‘What do I think about biometric proof of personhood?’ In the opening statement, he wrote that:

One of the trickier, but potentially one of the most valuable, gadgets that people in the Ethereum community have been trying to build is a decentralized proof-of-personhood solution.

With Rarimo’s Proof-of-Humanity (POH) use case launching on the 22nd of August, Rarimo’s thinking and Vitalik’s align. Proof-of-personhood (POP) or Proof of Humanity confirms simply that a user is a human and not a bot. With the proliferation of AI and AI-generated bots, the need for such proof is growing increasingly urgent.

Proof-of-Personhood — the Challenges

Yet despite the seemingly simple proposition of POH, there are significant technical and social challenges. Firstly, there is the issue of privacy. How do we allow people to be able to prove they are human without being forced to reveal personal information that could identify them? Secondly, there is the issue of decentralization. Digital identities are powerful and potentially dangerous tools, so how do we build a system that prevents abuse from centralized organizations?

Biometric vs Social Graph Verification

Vitalik takes Worldcoin as a jumping-off point to examine the virtues and vulnerabilities of different Proof-of-Humanity models. Primarily, he compares social graph verification which leverages social interactions with biometric Proof-of-Personhood, distinguishing between biometric solutions which use general hardware and those that use specialized hardware. Worldcoin falls into the latter category and uses ‘Orbs:’ futuristic-looking spheres, to scan people’s irises.

Ultimately, Vitalik concludes that:

There is no ideal form of proof of personhood. Instead, we have at least three different paradigms of approaches that all have their own unique strengths and weaknesses…What we should ideally do is treat these three techniques as complementary, and combine them all.

These strengths are weaknesses are represented in the chart below:

Rarimo’s Proof-of-Humanity Use Case

Vitalik’s blog can be read in full here. Rarimo shares his conclusion that Proof-of-Humanity is strongest when different verification methods are combined and, accordingly, is working on a use case that does just this. Rarimo cannot wait to launch it and to start contributing to the emergent POH space. Stay tuned for updates!




Making digital identities & the decentralized social layer multi-chain