Cacatoid

An iOS app that searches for the private key to unsolved Bitcoin Puzzle addresses, running a multi-threaded native key search directly on your iPhone or iPad.

⚠️ For fun and learning. The puzzles Cacatoid targets (71, 72, 73) have key spaces of roughly 2⁷⁰–2⁷². A modern iPhone checks hundreds of thousands to a few million keys per second, so the odds of an actual hit are astronomically small. Treat this as a demonstration of secp256k1 cryptography and iOS background processing, not a get-rich plan.

Screenshots

Home	Running	Match Found

What it does

The Bitcoin puzzle transaction is a well-known challenge where puzzle n has a private key somewhere in the range [2^(n-1), 2^n - 1], and the matching address is public. Cacatoid picks a target puzzle, derives the compressed P2PKH address for candidate keys, and compares it against the target.

• Puzzle 20 — already solved; included as a built-in smoke test because its tiny range is found almost instantly, exercising the whole pipeline end to end.
• Puzzles 71, 72, 73 — currently unsolved targets.

When a key matches, the app shows the private key (hex), WIF, and address and alerts the user immediately.

How it works

ContentView (SwiftUI) ──▶ SearchViewModel ──▶ searcher_start() (C++) ──▶ worker threads

• Native search (ios/Cacatoid/Native/) — all cryptography and key iteration runs in C++: secp256k1 point multiply, SHA-256, RIPEMD-160, and Base58Check. Each worker thread samples random keys from the full puzzle range independently, using a time + ASLR-seeded RNG to avoid duplicate sequences across threads. A monitor thread reports throughput to Swift about twice a second; a match fires a callback immediately.
• Swift bridge (searcher_bridge.h) — a thin C interface (searcher_start, searcher_stop) called from Swift via a bridging header.
• UI (ContentView + SearchViewModel) — pick a puzzle, start/stop, and watch the current key, keys/sec, and total-checked counters update live.

128-bit range math uses unsigned __int128, supported by clang on 64-bit Apple Silicon and A-series targets.

Download

Grab the latest .ipa from the Releases page and sideload it with AltStore or Sideloadly.

Building from source

Requires Xcode 15+ with the iOS SDK.

cd ios
xcodebuild -project Cacatoid.xcodeproj \
           -scheme Cacatoid \
           -configuration Release \
           -destination 'generic/platform=iOS' \
           archive -archivePath build/Cacatoid.xcarchive

xcodebuild -exportArchive \
           -archivePath build/Cacatoid.xcarchive \
           -exportPath build/ \
           -exportOptionsPlist ExportOptions.plist

Or open ios/Cacatoid.xcodeproj in Xcode and hit Product → Archive.

Project layout

Path	Purpose
ios/Cacatoid/CacatoidApp.swift	App entry point
ios/Cacatoid/ContentView.swift	SwiftUI UI and live stats
ios/Cacatoid/SearchViewModel.swift	UI state, start/stop
ios/Cacatoid/Native/searcher.cpp	Threaded search core
ios/Cacatoid/Native/searcher_bridge.h	C interface for Swift
ios/Cacatoid/Native/secp256k1_utils.*	secp256k1 wrapper
ios/Cacatoid/Native/sha256.*, ripemd160.*, base58.*	Crypto primitives
ios/lib/libsecp256k1.a	Static secp256k1 compiled for iOS arm64

License

No license specified yet.