Attribute Proof

The core capability to reveal specific, granular attributes from a larger credential without exposing the entire data set. For example, proving you are over 21 from a driver's license without revealing your exact birth date, address, or license number. This minimizes data leakage and enhances user control.

Enables verification that a statement about an attribute is true without revealing the attribute itself or any underlying evidence. Built using Zero-Knowledge Proofs (ZKPs) like zk-SNARKs or Bulletproofs. For instance, proving you have a sufficient balance in an account without revealing the actual balance or transaction history.

Prevents different proofs derived from the same credential from being linked together or to the holder's identity. This is achieved through cryptographic techniques like random blinding factors. Essential for preventing profiling across multiple service interactions, preserving user anonymity.

Proofs are mathematically verifiable by any party using public parameters. Verification relies on digital signatures (e.g., BBS+) or ZKP verification keys. This provides strong, trust-minimized assurance of the proof's validity and the issuer's authenticity, eliminating reliance on the prover's honesty.

The user (holder) generates and presents proofs directly from credentials stored in their digital wallet. This shifts control from centralized issuers and verifiers to the individual, enabling self-sovereign identity principles. The issuer cannot track where or when a proof is used.

Supports proving statements about attributes rather than their raw values. Common predicates include:

• Greater than / Less than (e.g., age > 18)
• Set membership (e.g., country IN ['US', 'CA'])
• Boolean logic (e.g., (citizen = true) AND (age >= 65))

A user can prove their credit score exceeds a lender's minimum threshold (e.g., score > 700) without disclosing the exact score or their full credit history. The proof is generated off-chain from a verifiable credential issued by a credit bureau. This allows for permissioned DeFi lending and undercollateralized loans based on proven, yet private, financial reputation.

An investor can prove they hold a minimum amount of a specific asset (e.g., ETH balance > 32) or a diversified portfolio to qualify for a whitelist, governance vote, or exclusive service. The proof cryptographically verifies the balance against a specific block header state root, without revealing the wallet address or other asset holdings. This is foundational for sybil-resistant airdrops and gated communities.

A company can prove specific business metrics (e.g., revenue > $1M, KYC status = verified) to a smart contract to access a supply chain financing pool or insurance product. The proof is generated from a signed, tamper-evident data feed, allowing trust-minimized verification of real-world attributes for on-chain conditional logic, without exposing sensitive corporate data.

Users can prove social graph attributes, such as being followed by a specific account or having a minimum follower count, to access gated content or communities. These proofs, built from verifiable credentials or on-chain activity, enable contextual privacy—revealing only what's necessary for an interaction—and form the basis for portable, composable reputation systems.

Attribute proofs allow portable, verifiable reputation. A user can prove their GitHub contribution history, DeFi protocol usage, or community moderation role across different applications. This enables systems where trust is based on proven past behavior rather than capital alone, forming the basis for decentralized social networks and professional networks.

Attribute proofs enable trust-minimized state bridging. Instead of locking and minting assets, a user can prove ownership of an asset on Chain A to mint a representation on Chain B. This also applies to proving membership in a DAO on another chain or demonstrating historical yield earned in a different ecosystem to qualify for airdrops or rewards.

A core cryptographic primitive enabling attribute proofs. ZKPs allow a prover to convince a verifier of a statement's truth (e.g., "I am over 18") without revealing the underlying data (the exact birth date). This provides privacy-preserving verification and is fundamental for selective disclosure.

• Example: Using a zk-SNARK to prove a credit score exceeds 700 without revealing the score.

The principle of revealing only the specific attributes or predicates required for a transaction, minimizing data exposure. This reduces privacy risk and attack surface.

• Mechanism: A user presents a verifiable credential but uses a cryptographic proof to disclose only that country = "US" and age >= 21, while keeping their name and exact address hidden.

The trustworthiness of an attribute proof depends on the credential issuer. Decentralized Identifiers (DIDs) and Verifiable Data Registries allow issuers (e.g., universities, governments) to publish their public keys, enabling verifiers to cryptographically check signatures without a central authority.

• Security Implication: Proofs are only as trustworthy as the issuer's DID and the security of its private keys.

A critical security feature preventing the sharing or resale of proofs. Techniques like signature-based proofs bound to a holder's specific DID or semaphore-style nullifiers ensure a proof generated for one user cannot be used by another.

• Prevents: Sybil attacks and the black-market trading of access credentials.

Mechanisms to invalidate attribute proofs if credentials are compromised or expire. This is a major trust challenge in decentralized systems.

• Methods: Revocation Registries (e.g., W3C Status List), accumulator-based schemes, or time-bound proofs requiring frequent state updates from the issuer.

The rules a verifier (e.g., a dApp) sets for accepting proofs. A secure system requires clear, auditable policy logic.

• Components: Specifying trusted issuer DIDs, required attribute schemas, maximum proof age, and supported cryptographic suites. On-chain verifier contracts make these policies transparent and tamper-proof.