ZkpClient — internals

High-level usage is documented on ZkpClient. This page lists internal services and architecture for tooling, debugging, or custom flows.

Architecture

ZkpClient is a thin composition root. It holds no business logic — it wires platform-specific backends into services and exposes a ClientContext that wallets consume internally.

ZkpClient (composition root)
  ├── SolverService    ← ISolverBackend (WASM / native)
  ├── ProverService    ← IProverBackend (WASM / native) + CircuitLoader
  ├── publicClient     ← viem (chain reads)
  ├── RelayerClient    ← optional HTTP relayer
  └── tokens map       ← currency → contract address

ClientContext

The internal interface passed to ZkpWallet. Not part of the public SDK API.

Field	Type	Description
solverService	SolverService	Self-initializing — ElGamal decrypt + discrete-log solve
proverService	ProverService	Self-initializing — circuit loading + proof generation
publicClient	PublicClient	viem client for chain reads
chain	Chain	viem chain object
rpcUrl	string	RPC endpoint
storage	StorageAdapter?	Persistent cache for history and balances
relayerAccess	IRelayerAccess	hasRelayer() / getRelayer()
tokens	ReadonlyMap<string, Address>	Currency → token contract address
createWalletClient	(account) => WalletClient	Factory for viem write clients

Services

SolverService

Wraps an ISolverBackend. Self-initializing — calls ensureReady() on first decrypt.

• decrypt(ct, sk) — ElGamal decrypt + discrete-log solve
• ensureReady() — eagerly init the solver backend
• destroy() — teardown

ProverService

Wraps an IProverBackend + CircuitLoader. Self-initializing — loads circuits on first proof generation.

• generateTransferProof(witness) — concealed transfer proof
• generateToPublicProof(params) — concealed → public proof
• ensureReady() — eagerly load circuits
• prewarm() — dummy proof to warm JIT
• destroy() — teardown

Transaction decoding (standalone helpers)

Function	Description
decryptTransferFromTx(publicClient, solverService, txHash, sk, bpk)	Incoming transfer amount
decryptOutgoingTransferFromTx(publicClient, solverService, txHash, sk, bpk)	Outgoing transfer amount
getTransferParties(publicClient, txHash)	Parse sender/recipient BPKs from calldata

Default backends (web / Node)

• DlogSolverBackend — WASM discrete-log solver (ISolverBackend).
• WasmProverBackend — Noir JS + bb.js (IProverBackend with prove).

Custom mobile/native stacks implement the interfaces in @zk-privacy/core/types and pass them in ZkpClientConfig.

Helpers

• DEFAULT_CHAIN_CONFIG — per-chain token addresses, RPC, relayer URL presets.
• resolveRecipient(to: Recipient) — normalize zk1 string or Point recipient.