NextGraph Glossary

NextGraph Glossary.md

Here’s a glossary of technical terms and concepts related to NextGraph’s architecture, data management, and implementation techniques:

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A-C

• Bloom Filter:
  A probabilistic data structure used in decentralized indexes to efficiently check if a feed might contain specific data (e.g., vouchers in USD) without storing the full dataset. Reduces network overhead during searches.

• Capability Token (UCAN):
  A cryptographically signed token (User Controlled Authorization Network) granting granular permissions (e.g., read/write access to a voucher). Used to enforce selective replication and secure transactions.

• Conflict-Free Replicated Data Type (CRDT):
  A data structure that automatically resolves merge conflicts across peers, enabling offline-first apps. NextGraph uses CRDTs for local repositories to sync vouchers and transactions.

• Cryptographic Threshold Signatures:
  A scheme where a private key is split into shares, requiring a threshold (e.g., 3/5 jurors) to collaborate for decryption or signing. Used for secure evidence access in arbitration.

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D-F

• EigenTrust Algorithm:
  A decentralized reputation scoring system that computes trust scores based on a graph of interactions (e.g., successful transactions). Combines with EXO-REP tokens for Sybil-resistant jury selection.

• Encryption at Rest:
  Data stored locally (e.g., in ~/.local/share/org.nextgraph.app) is encrypted using AES-256-GCM. Keys are derived from user PINs or biometrics.

• Finite State Machine (FSM):
  A computational model where a system transitions between predefined states (e.g., Listed → Pending → Completed). Used in NextGraph’s WASM-based smart contracts.

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G-L

• Homomorphic Encryption (HE):
  Allows computation on encrypted data (e.g., querying voucher amounts without decrypting). Future-proofs privacy for federated queries in Exonomy.

• IPFS (InterPlanetary File System):
  A decentralized storage protocol for evidence (e.g., chat logs, timestamps). Provides content-addressed, tamper-proof storage.

• JSON-LD:
  A JSON-based format for linked data, using @context to define semantic relationships. Represents vouchers and transactions in NextGraph.

• Local-First Repository:
  A CRDT-backed database stored on-device. Exonomists’ vouchers and transactions persist offline and sync only with authorized peers.

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M-P

• Noise Protocol Framework:
  A cryptographic protocol for encrypting peer-to-peer communication (e.g., voucher transfers). Used in NextGraph’s libp2p networking layer.

• Pinning/Unpinning:

  • Pin: Persistently replicate a feed/voucher to a device (e.g., after following an Exonomist).
  • Unpin: Remove replicated data to free storage.

• Pub/Sub Overlay:
  A messaging layer where peers subscribe to topics (e.g., feed:Alice). Updates (e.g., new vouchers) are pushed only to subscribers.

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Q-S

• RDF (Resource Description Framework):
  A semantic data model using triples (subject-predicate-object) to represent vouchers, transactions, and relationships. Enables SPARQL queries.

• Replication Rules:
  Policies dictating how data propagates. In Exonomy, vouchers replicate only during transactions or follows (not globally).

• SPARQL:
  A query language for RDF data. Used to search vouchers (e.g., SELECT ?voucher WHERE { ?voucher exo:currency cbdc:USD }).

• Soulbound Token (SBT):
  A non-transferable token (e.g., EXO-REP) bound to an Exonomist’s identity. Reputation tokens are SBTs to prevent Sybil attacks.

• Sybil Resistance:
  Mechanisms (e.g., staking, trust graphs) to prevent fake identities from spamming the network. Critical for arbitration jury selection.

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T-Z

• Threshold Cryptography:
  A method where cryptographic operations (e.g., decryption) require multiple parties to collaborate. Used to securely access encrypted evidence.

• WASM (WebAssembly):
  A portable binary format for smart contracts. NextGraph compiles contracts (e.g., voucher sales) to WASM for cross-platform execution.

• Zero-Knowledge Proof (ZKP):
  A cryptographic proof (e.g., zk-SNARK) that validates a claim (e.g., "voucher was valid") without revealing underlying data.

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Exonomy-Specific Terms

• EXO-REP:
  A reputation token minted/staked by jurors. Earned via honest arbitration participation, slashed for malicious behavior.

• Selective Replication:
  Data (e.g., vouchers) is only copied to devices involved in a transaction or follow relationship, minimizing storage overhead.

• Voucher Lifecycle:
  States include ForSale, Pending, Completed, and Revoked. Managed by smart contracts to enforce rules (e.g., expiry).

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Key Techniques

1. Shamir Secret Sharing: Splits encryption keys into shares for threshold decryption.
2. Last-Write-Wins (LWW): CRDT merge strategy resolving conflicts using timestamps.
3. Arbitration Escrow: Smart contracts freeze vouchers until disputes are resolved.
4. Post-Compromise Recovery: Resets keys if a device is breached.