Crate zcash_client_backend

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Expand description

A crate for implementing Zcash light clients.

zcash_client_backend contains Rust structs and traits for creating shielded Zcash light clients.

§Design

§Wallet sync

The APIs in the data_api::chain module can be used to implement the following synchronization flow:

                         ┌─────────────┐  ┌─────────────┐
                         │Get required │  │   Update    │
                         │subtree root │─▶│subtree roots│
                         │    range    │  └─────────────┘
                         └─────────────┘         │
                                                 ▼
                                            ┌─────────┐
                                            │ Update  │
          ┌────────────────────────────────▶│chain tip│◀──────┐
          │                                 └─────────┘       │
          │                                      │            │
          │                                      ▼            │
   ┌─────────────┐        ┌────────────┐  ┌─────────────┐     │
   │  Truncate   │        │Split range │  │Get suggested│     │
   │  wallet to  │        │into batches│◀─│ scan ranges │     │
   │rewind height│        └────────────┘  └─────────────┘     │
   └─────────────┘               │                            │
          ▲                     ╱│╲                           │
          │      ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─              │
     ┌────────┐         ┌───────────────┐       │             │
     │ Choose │  │      │Download blocks│                     │
     │ rewind │         │   to cache    │       │             │
     │ height │  │      └───────────────┘           .───────────────────.
     └────────┘                 │               │  ( Scan ranges updated )
          ▲      │              ▼                   `───────────────────'
          │               ┌───────────┐         │             ▲
 .───────────────┴─.      │Scan cached│    .─────────.        │
( Continuity error  )◀────│  blocks   │──▶(  Success  )───────┤
 `───────────────┬─'      └───────────┘    `─────────'        │
                                │               │             │
                 │       ┌──────┴───────┐                     │
                         ▼              ▼       │             ▼
                 │┌─────────────┐┌─────────────┐  ┌──────────────────────┐
                  │Delete blocks││   Enhance   ││ │Update wallet balance │
                 ││ from cache  ││transactions │  │  and sync progress   │
                  └─────────────┘└─────────────┘│ └──────────────────────┘
                 └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─

§Feature flags

  • lightwalletd-tonic — Enables the tonic gRPC client bindings for connecting to a lightwalletd server.
  • lightwalletd-tonic-transport — Enables the transport feature of tonic producing a fully-featured client and server implementation
  • transparent-inputs — Enables receiving transparent funds and shielding them.
  • orchard — Enables receiving and spending Orchard funds.
  • test-dependencies — Exposes APIs that are useful for testing, such as proptest strategies.

§Experimental features

  • unstable — Exposes unstable APIs. Their behaviour may change at any time.
  • unstable-serialization — Exposes APIs for unstable serialization formats. These may change at any time.
  • unstable-spanning-tree — Exposes the data_api::scanning::spanning_tree module.

Modules§

  • address
    Structs for handling supported address types.
  • data_api
    Utilities for Zcash wallet construction
  • encoding
    Encoding and decoding functions for Zcash key and address structs.
  • fees
  • keysorchard or sapling or transparent-inputs
    Helper functions for managing light client key material.
  • proposal
    Types related to the construction and evaluation of transaction proposals.
  • proto
    Generated code for handling light client protobuf structs.
  • scan
  • scanning
    Tools for scanning a compact representation of the Zcash block chain.
  • serializationunstable-serialization
  • wallet
    Structs representing transaction data scanned from the block chain by a wallet or light client.
  • zip321
    Reference implementation of the ZIP-321 standard for payment requests.

Structs§

Enums§

  • PoolType
    A value pool in the Zcash protocol.
  • ShieldedProtocol
    A Zcash shielded transfer protocol.
  • TransferType
    An enumeration of the possible relationships a TXO can have to the wallet.

Functions§