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Hashmerchant

Hashmerchant lets Terp validators collectively attest to foreign chain state roots. Once 2/3 voting power agrees on a root, it is stored on-chain and dispatched to subscribed CosmWasm contracts. A Pallas curve reduction makes the attested roots usable in ZK circuits at a fraction of the cost of proving raw Keccak256 or SHA256 in-circuit.

Documentation

Page	What it covers
Architecture	System map, component relationships, data flow, wire format
Building Apps	Patterns for consuming hash roots: sudo callbacks, direct queries, ZK credentials, private airdrops
Tree Types	Supported and planned hash algorithms, how to add new chains, the Pallas reduction
Custody	Signing backends — local keys, TKMS, custom (Cloud KMS, HSM, threshold)
Sidecar	Running and configuring `hash-market-server` and `hash-market-client`
FROST privval	Threshold CometBFT signing in the sidecar: presig inventory, HRS, Noise session
Headstash Server	Privacy note/key server, secp256k1 auth, PIR protocol, snap integration
Blob DA Design	Future: EIP-4844-inspired temporary blob storage, sub-store mirroring, fee manifold

Repository layout

tools/
  hash-market/           ← Validator sidecar (Rust, feature-gated)
    src/
      msg/               ← Protobuf types (anybuf, no codegen)
      custody/           ← Signing backends (local, TKMS)
      ve/                ← Vote extension signing + verification
      eth/               ← Ethereum JSON-RPC client
      pallas/            ← Keccak256 → Pallas Fp reduction
      transport/         ← gRPC / HTTP poll / WebSocket listeners
      server/            ← Axum HTTP server (CometBFT callbacks)
      client/            ← ETH proof polling loop
      bin/
        server.rs        ← hash-market-server binary
        client.rs        ← hash-market-client binary
    docs/                ← You are here

  headstash-server/      ← Privacy note + key server (Rust)
    src/
      pir/               ← XOR-based Private Information Retrieval
      store/             ← File-based KV storage
      middleware/        ← secp256k1 + JWT auth dispatch
      main.rs            ← Axum server with 11 API endpoints

  snap-n-pull-js/        ← MetaMask snap (TypeScript)
  merkle-server/         ← BLAKE3 Merkle proof server (Rust)

terp-core/
  x/hashmerchant/        ← On-chain Cosmos SDK module (Go)
    keeper/
      vote_ext.go        ← ABCI++ vote extension handlers
      msg_server.go      ← gRPC transaction handlers
    types/
      types.proto        ← Canonical protobuf definitions

At a glance

               Foreign Chain                    Terp Chain
            ┌──────────────────┐           ┌───────────────────┐
            │  State Root      │           │  x/hashmerchant   │
            │  (Keccak/SHA)    │           │                   │
            └────────┬─────────┘           │  RegisteredChain  │
                     │                     │  HashRoot         │
                     ▼                     │  HashPairTicket   │
            ┌──────────────────┐           │  EscrowRecord     │
            │  hash-market     │           │                   │
            │  client          │           │  sudo callbacks   │──► CosmWasm
            │  (polls + proves)│           │  to funded        │    contracts
            └────────┬─────────┘           │  contracts        │
                     │                     └────────▲──────────┘
                     ▼                              │
            ┌──────────────────┐           vote extensions
            │  hash-market     │──────────────────┘
            │  server          │
            │  (signs + serves)│
            └──────────────────┘