Masa Invents the zkSBT to Power Privacy-Preserving Data Exchange
At Masa, we believe the internet has a fundamental privacy problem: users lack secure ways to control, consent to, and profit from the use of their personal data. This issue is greatly amplified in the era of AI, which relies on harvesting vast troves of user data to train algorithms.
Our solution is to pioneer cutting-edge cryptography like zero-knowledge proofs (ZKP) and homomorphic encryption (HME) to enable private data exchange at a global scale. A core component at the center of the Masa Network is our invention, the zero-knowledge Soulbound token (zkSBT). Masa’s invention of zkSBT has been summarized in an academic paper titled “Private Identity-Related Attribute Verification Protocol Using Soulbound Tokens and Zero-Knowledge Proofs.” The paper has been peer-reviewed and debuted at the 7th Cyber Security in Networking Conference (CSNET).
Read the full paper: “Private Identity-Related Attribute Verification Protocol Using SoulBound tokens and Zero-Knowledge Proofs”
To celebrate the publishing of Masa’s zkSBT paper, today we are diving into the details of zkSBT, its applications, and technical innovations.
What is a zkSBT?
A zkSBT is a non-transferable NFT that allows users to store private encrypted data onchain or offchain entirely securely. Think of it as your personal data locker: your data is encrypted using your public key, so only you can decrypt it with your private key and through signed transactions. This grants verifiable data access to specific 3rd parties based on permissions that you program into your zkSBT or developers deploy through zkSBT smart contracts. Important to note that Masa fully supports EIP-4337: Account Abstraction, which empowers you to use social and email login to manage your zkSBT, eliminating the complexity of private key management.
Why invent the zkSBT?
The current state of the internet is rampant with privacy issues, and users have no secure way to preserve, manage, or monetize their data.
zkSBTs empower people to manage consent and data-sharing permissions and selectively disclose their data in a fully self-sovereign way. People maintain control of their data and keys through interfaces like browser extensions, mobile apps, and social logins using account abstraction to grant access to the data stored within the zkSBT. The Masa SDK powers this interaction.
zkSBTs enable the core user-centric design of the Masa Network and users’ data private by default. By minting zkSBTs on low-gas or gasless blockchain architecture, we achieve efficient large-scale issuance of users’ data access tokens. ZkSBTs are a cost-effective, scalable, and dynamic way to manage data associated with and controlled by users. By utilizing zkSBTs we can manage 100s of millions of users’ data in an efficient architecture.
At Masa, we set out to give back the power to permission, manage and monetize data to billions of users, while also allowing millions of businesses and developers to build a new class of privacy-preserving, decentralized applications on Masa’s underlying zk-Data Network. We are extremely bullish on the use cases of zkSBTs: from enabling privacy-preserved analytics, to powering interest-based ad targeting without exposing personal data, to allowing Machine Learning model auditing without revealing underlying data or methodology. Together with our decentralized oracle network for privacy-preserving data processing and exchange, zkSBTs form the cornerstone of the Masa zero-knowledge Data Network.
Masa is solving both the user problem of consented and private data, while also catering to the market demand of user behavioral data through our zk-data Network.
How zkSBTs Work: A Technical Deep Dive
The zkSBT combines Soulbound Token design with advanced zero-knowledge cryptography in an innovative way to enable privacy-preserving identity systems. Here is a technical look under the hood at how zkSBTs achieve this:
- Data Encryption: The issuer encrypts identity data using the public key of the identity holder. This ensures only they can decrypt it with their private key. RSA or ECC asymmetric encryption can be used.
- Onchain Data: The encrypted data is stored in the zkSBT along with a hash of the plaintext data generated using a ZK-friendly hash like Poseidon. The hash enables integrity checks.
- ZK-Proofs: The identity holder can generate a ZKP to prove claims about their data without revealing anything beyond what’s being proven.
- ZK-Circuits: These define the proofs with private inputs (encrypted data) and public inputs (e.g., data hash, thresholds).
- Keys: Circuits use cryptographic keys — a proving key for the prover and a verification key for the verifier — generated from a secret parameter.
- Verification Contracts: Smart contracts automatically verify proofs on-chain using the verification key and public inputs. They check the zkSBT matches, too.
- Decryption: The identity holder decrypts their data with their private key to generate proofs. No raw data is exposed.
- Selective Disclosure: Identity holders share only the proofs, selectively disclosing identity attributes as needed.
- User Control: zkSBT design gives users control over their private data and keys. The issuer cannot access raw data.
By bringing together Soulbound Tokens, public key encryption, zero-knowledge proofs, and specialized circuits/contracts, zkSBTs enable a new paradigm for self-sovereign digital identity where users control private data sharing.
Announcing zkSBT at CSNET 2023
We unveiled this zkSBT invention at the 7th Cyber Security in Networking Conference (CSNET) in Montreal in October 2023. Our peer-reviewed paper details the protocol behind zkSBTs.
By combining Soulbound Token design with advanced zero-knowledge cryptography in a novel way, zkSBTs overcome the limitations of previous identity and data ownership schemes. zkSBTs balance user control with selective data disclosure to drive equitable value exchange between data providers and consumers.
The Road Ahead — The Masa zk-Data Network
With the zkSBT as our core user-layer building block, we are rolling out data monetization features that let users earn rewards in stablecoins and crypto when their data creates value. Masa has 850k user wallets on its network and has integrated with 70+ business, developers and ecosystem partners, including leading projects such as Injective, QuickSwap, Polygon, Celo and more, driving massive network effects, accelerating user growth, data depth, and data breadth. This unlocks the world’s largest permissionless data layers that empower billions of uses, enabling millions of businesses to be built on the Masa Network.
Masa is proud to bring this new primitive in decentralized technology to life. zkSBTs move us closer to our vision of a user-owned data economy where innovation thrives while privacy is guaranteed. The possibilities for global-scale data exchange unlocked by zkSBTs are just beginning!
Start Building on Masa
Ready to be part of the future of decentralized data? Developers worldwide are invited to build groundbreaking privacy-preserving applications on top of Masa’s zero-knowledge data network.
With the zkSBT unveiled, developers have an essential building block to leverage in their various applications with unlimited use cases. zkSBTs empower users to own and control their data while enabling selective disclosure through advanced cryptography.
Developers can access the tools and resources needed to integrate zkSBTs into their applications:
- Masa SDK: The software development kit makes adding a zkSBT integration easy.
- Developer Documentation: Guides, API references, and more outline how to mint, verify, and manage zkSBTs programmatically.
- Developer Community: Join other builders working on private data apps and share best practices in our Discord.
With Masa’s exponential user growth and continued improvements to network scalability, now is the perfect time to start leveraging Masa’s zero-knowledge data marketplace. Be at the forefront of the Web3 data revolution.
Get started today by reviewing the developer documentation or joining our Discord community. Share your ideas and let us know how we can support your next breakthrough privacy project built on Masa!
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