gem-hunter

A Zcash Lightweight Client SDK for iOS, maintained by the Zcash Open Development Lab (ZODL). It originated as the Electric Coin Company's ZcashLightClientKit; ECC neither maintains nor reviews this fork. It is under active development. Please be advised of the following:

• This code currently is not audited by an external security auditor, use it at your own risk
• We are actively changing the codebase and adding features where/when needed

🔒 Security Warnings

• The Zcash iOS Wallet SDK is experimental and a work in progress. Use it at your own risk.
• Developers using this SDK must familiarize themselves with the current threat model, especially the known weaknesses described there.
• To report a security vulnerability, follow SECURITY.md. Do not open a public issue.

Add a package with the source "https://github.com/zodl-inc/zodl-swift-wallet-sdk.git" in either Xcode's GUI or in your Package.swift file. The package is named zodl-swift-wallet-sdk and its library product and module are ZODLSwiftWalletSDK. SwiftPM derives the package: argument of .product(name:package:) from the last path component of the repository URL, which now matches the package name. 6.0.0 is the first release that contains the rename; until it is published, depend on a revision of main:

dependencies: [
    .package(url: "https://github.com/zodl-inc/zodl-swift-wallet-sdk.git", from: "6.0.0")
],
targets: [
    .target(
        name: "MyWallet",
        dependencies: [
            .product(name: "ZODLSwiftWalletSDK", package: "zodl-swift-wallet-sdk")
        ]
    )
]

import ZODLSwiftWalletSDK

If you want to include a pre-release version e.g. 3.1.0-rc.1 in an Xcode project you will need to specify it with the commit sha instead, as it does not appear that Xcode supports 'meta data' from semantic version strings for swift packages (at the time of writing).

This SDK includes Rust code that provides the core cryptographic and wallet functionality via FFI. For most SDK development, you don't need to build the Rust code - SPM automatically downloads pre-built binaries.

If you need to modify the Rust code in rust/:

# One-time setup (builds from source and configures the workspace)
./Scripts/init-local-ffi.sh

# Open the development workspace
open ZcashSDK.xcworkspace

# Fast incremental rebuild after changes
./Scripts/rebuild-local-ffi.sh

See docs/LOCAL_DEVELOPMENT.md for detailed instructions.

The best way to run tests is to open "Package.swift" in Xcode and use the Test panel and target an iOS device. Tests will build and run for a Mac target but are not currently working as expected.

There are three test targets grouped by external requirements:

1. OfflineTests
   • No external requirements.
2. NetworkTests
   • Require an active internet connection.
3. DarksideTests
   • Require an instance of lightwalletd to be running while the tests are being run, see below for some information on how to set up. (Darkside refers to a mode in lightwalletd that allows it to be updated to represent/mock different states of the underlying blockchain.)

The DarksideTests test target depend on a lightwalletd server instance running locally (or remotely). For convenience, we have added a universal (Mac) lightwalletd binary (in `Tests/lightwalletd/lightwalletd) and it can be run locally for use by the tests with the following command:

Tests/lightwalletd/lightwalletd --no-tls-very-insecure --data-dir /tmp --darkside-very-insecure --log-file /dev/stdout

You can find out more about running lightwalletd, from the main repo https://github.com/zcash/lightwalletd.

The LIGHTWALLETD_ADDRESS environment variable can also be added to your shell of choice and xcodebuild will pick it up accordingly.

We advise setting this value as a secret variable on your CD/CI environment when possible.

There are a lots of good logging tools for iOS. So we'll leave that choice to you. ZODLSwiftWalletSDK relies on a simple protocol to bubble up logs to client applications, which is called Logger (kudos for the naming originality...)

public protocol Logger {
    
    func debug(_ message: String, file: String, function: String, line: Int)
    
    func info(_ message: String, file: String, function: String, line: Int)
    
    func event(_ message: String, file: String, function: String, line: Int)
    
    func warn(_ message: String, file: String, function: String, line: Int)
    
    func error(_ message: String, file: String, function: String, line: Int)
    
}

You have a few different options when it comes to logging:

1. Leave it to the SDK. It will use its own Logger with sensible defaults. For this option, simply omit the loggingPolicy parameter when creating the Initializer

2. Provide a custom logger. For this option, do the following: a). have one class conform to the Logger protocol b). inject that logger when creating the Initializer by passing a loggingPolicy of .custom(yourLogger)

3. No logging. The SDK will not log any events. For this option, pass a loggingPolicy of .noLogging when creating the Initializer

For more details look the Sample App's AppDelegate code.

We don't like reinventing the wheel, so we gently borrowed swift lint rules from AirBnB which we find pretty cool and reasonable.

The CompactBlockProcessor is responsible for downloading and processing blocks from the lightwalletd. Since the inception of the SDK the blocks were processed in a linear order up to the chain tip. Latests SDK has introduced brand new algorithm for syncing of the blocks. It's called Spend before Sync and processes blocks in non-linear order so the spendable funds are discovered as soon as possible - allowing users to create a transaction while still syncing.

This project follows semantic versioning with pre-release versions. An example of a valid version number is 1.0.4-alpha11 denoting the 11th iteration of the alpha pre-release of version 1.0.4. Stable releases, such as 1.0.4 will not contain any pre-release identifiers. Pre-releases include the following, in order of stability: alpha, beta, rc. Version codes offer a numeric representation of the build name that always increases. The first six significant digits represent the major, minor and patch number (two digits each) and the last 3 significant digits represent the pre-release identifier. The first digit of the identifier signals the build type. Lastly, each new build has a higher version code than all previous builds. The following table breaks this down:

This repo contains demos of isolated functionality that this SDK provides. They can be found in the examples folder.

Examples can be found in the Demo App.

Copyright © 2026 Znewco, Inc. (d/b/a Zcash Open Development Lab)

ZODL Swift Wallet SDK is free software, licensed under the GNU Affero General Public License, version 3 only (AGPL-3.0-only). See LICENSE.

In short: you may use, study, modify, and redistribute ZODL Swift Wallet SDK, but if you incorporate it into an application, the complete source of that application must be made available under the AGPL to its users, including users who interact with it over a network.

If those terms don't fit your project, commercial licenses are available — see COMMERCIAL-LICENSE.md. Official Zodl builds distributed through the Apple App Store are released by Znewco under separate terms; no App Store distribution permission is granted to AGPL licensees — see LICENSE-EXCEPTIONS.md.

ZODL Swift Wallet SDK is derived from ZcashLightClientKit, Copyright (c) 2020 Zcash, which was made available under the MIT License; that license is reproduced in LICENSE-MIT. It also depends on the Zcash Rust crates (librustzcash and related) and other third-party libraries, which are separately licensed by their respective copyright holders and are not covered by this notice.