Glossary
This glossary provides detailed definitions for concepts frequently referenced across ZKID’s documentation, architecture, and ecosystem design.
Anchoring
The process of hashing identity registry state and anchoring the hash to Bitcoin (SHA-256) for global immutability. Anchoring acts as ZKID’s censorship-resistant truth layer, ensuring state cannot be rewritten or manipulated.
Arweave
A decentralized long-term data storage network. ZKID uses Arweave to store compressed identity metadata, credential references, and historical snapshots for verifiable permanence.
Batching
A mechanism where multiple identity operations (updates, issuances, revocations) are grouped into minimal Solana transactions or compressed updates to increase throughput and significantly reduce gas costs.
CID (Content Identifier)
A cryptographic pointer used to reference off-chain data stored in decentralized storage systems (IPFS, Arweave). ZKID uses CIDs for credential payloads, metadata, VC attestations, encrypted proofs, and historical logs.
Compressed Identity State
Identity attributes, credentials, and metadata stored in Solana’s compressed accounts. Allows the registry to scale to millions of identity states while staying cost-efficient.
Credential Issuance
The process by which a trusted issuer signs a cryptographically verifiable credential for a user’s DID. In ZKID, issuance is modular, privacy-preserving, and instantly verifiable across apps.
Cross-Layer Synchronization
ZKID’s system for synchronizing identity updates between Solana’s real-time state and Bitcoin anchoring checkpoints. Ensures consistency without cross-chain trust assumptions.
Decentralized Identifier (DID)
A cryptographically verifiable identifier controlled entirely by the user. ZKID supports DID-linked credentials, selective disclosure, and cross-app verification flows.
Decentralized Storage
Storage systems outside centralized servers. ZKID uses a hybrid approach:
Solana for compressed identity state
Arweave/IPFS for metadata and proof payloads
Bitcoin anchoring for global state integrity
Identity Graph
A Merkle-structured representation of a user’s digital identity, composed of attributes, credentials, attestations, reputation signals, and verifiable proofs.
Identity Snapshot
A hashed representation of identity registry state captured at a given time and anchored to Bitcoin. Enables historical audits and verifiable lineage.
Merkle Compression
Solana’s compressed data structure enabling low-cost identity storage. ZKID uses Merkle trees to store identity state with minimal on-chain footprint and fast verification.
Nullifier
A cryptographic marker used to prevent double-signalling, replay attacks, or proof re-use in zk-based identity flows. Critical for ensuring uniqueness and non-repeatability.
Selective Disclosure
A mechanism that allows users to disclose only what is necessary. Examples:
"I am over 18" without revealing date of birth
"I own this NFT" without exposing wallet history
"I am human" without biometric leakage
Self-Sovereign Identity
A model where the user fully controls their identity, credentials, and privacy preferences. Platforms cannot revoke, censor, or override identity.
Slashing
A penalty mechanism applied to validators who misbehave, underperform, or provide incorrect validation outputs. Slashing maintains the security of the identity ecosystem.
Solana Compression
The process of storing large amounts of identity data in compressed account structures. Enables:
extremely low storage cost
high throughput
state indexing
affordable queries
State Registration
The act of registering or updating identity objects on Solana via the ZK Identity Layer. All updates propagate to the validator network.
Validator Coordination Layer
The layer responsible for:
synchronizing state
verifying proofs
ensuring consistent updates
confirming issuer authenticity
validating anchoring intervals
Validators DO NOT control identity — they ensure correctness and integrity.
Validator Node
A participant in the ZKID network responsible for:
proof verification
registry synchronization
uptime
validator consensus
system fairness
Validators earn rewards for ensuring liveness and for processing identity operations.
Verifiable Credentials (VCs)
Digitally signed credentials linked to a DID. ZKID supports multiple credential types:
zk-based selective disclosure
human verification
asset ownership attestations
ecosystem-specific access credentials
reputation scores
ZK-Proofs
Cryptographic proofs that allow claims to be verified without revealing underlying private data. Used extensively for:
identity verification
credential validation
age checks
uniqueness
membership validation
ZK Verification Layer
The privacy enforcement module of ZKID. Enables:
private verification
minimal disclosure
encrypted attributes
instant proof validation
cross-app verifiability
ZK Identity Layer
The multi-layer identity architecture combining:
Bitcoin anchoring
Solana compressed registry
Credential issuance
ZK verification
Validator coordination
Forms the backbone of ZKID.
ZKID Validator Set
Node operators who ensure the correctness and trustlessness of ZKID. They maintain consistency, execute validation logic, and align incentives via staking.
ZK Reputation
A privacy-preserving reputation model where users can accumulate signals without exposing personal information or full history.
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