SwiftBindings.Apple.CryptoKit

SwiftBindings.Apple.CryptoKit

Native .NET bindings for Apple's CryptoKit framework — hashing, symmetric and authenticated encryption, key agreement, and signatures. These are not Objective-C proxy wrappers; they use .NET 10's native Swift interop for direct, high-performance calls into Swift APIs from C#.

📖 Full usage guide → — Swift→C# naming, authenticated encryption (AES-GCM/ChaChaPoly), hashing, HMAC, key agreement, ECDSA signatures, and the generic-overload caveats that decide which APIs are callable.

Installation

dotnet add package SwiftBindings.Apple.CryptoKit

Requirements

• .NET 10.0+
• Target framework: net10.0-ios26.2 (or -macos26.2 / -maccatalyst26.2 / -tvos26.2) or higher. The package is compiled against the iOS 26.2 SDK supplement, so your app's <TargetFramework> platform version must be ≥ 26.2 to restore it — an explicit lower TPV (e.g. net10.0-ios18.0) or a bare net10.0-ios whose installed workload defaults below 26.2 fails restore with NU1202. This is the compile-SDK pin, not your app's deployment minimum.
• Deployment minimum is separate — set your app's real minimum OS with <SupportedOSPlatformVersion> (independent of the TFM above). Individual APIs that need a newer OS at runtime are gated by generated [SupportedOSPlatform] attributes; the C# compiler flags a call that isn't valid for your target.
• macOS host for development

Usage

Hashing

using System.Text;
using CryptoKit;

var data = Encoding.UTF8.GetBytes("hello");
var digest = SHA256.Hash(data);

Authenticated encryption (AES-GCM)

using System.Text;
using CryptoKit;

var key = new SymmetricKey(SymmetricKeySize.Bits256);
var plaintext = Encoding.UTF8.GetBytes("secret message");

var sealedBox = AES.GCM.Seal(plaintext, key);
var recovered = AES.GCM.Open(sealedBox, key);

ChaChaPoly

var key = new SymmetricKey(SymmetricKeySize.Bits256);
var sealedBox = ChaChaPoly.Seal(plaintext, key);
var recovered = ChaChaPoly.Open(sealedBox, key);

Authenticated encryption with associated data

var aad = Encoding.UTF8.GetBytes("authenticated-header");
var sealedBox = AES.GCM.Seal(plaintext, key, aad);
// sealedBox.Ciphertext / sealedBox.Tag are exposed as byte[]

Documentation

• Usage guide (wiki) — full C# walkthrough of the binding surface
• Apple CryptoKit framework

Caveats

The primary AEAD round-trip (AES.GCM and ChaChaPoly Seal/Open) is verified end-to-end on both Mono JIT (simulator) and NativeAOT (device).

A residual cluster of ancillary CryptoKit APIs are emitted as [Obsolete("SB0001")] stubs and are not callable from C# in this release:

• HMAC constructor
• Signature generation (P-256/P-384/P-521 ECDSA signature(for:))
• HPKE Unwrap / Decapsulate / ExportSecret
• AES.GCM.Open<TAD> (the generic overload that takes authenticated-data of an arbitrary DataProtocol type)
• The 3-argument IsValidSignature(_:for:) overload

Tamper detection is exercised via wrong-key Open (which throws authenticationFailure) rather than the SealedBox(nonce:ciphertext:tag:) constructor (a Swift generic init the binding generator does not yet emit).

How It Works

These bindings are auto-generated by Swift Dotnet Bindings using .NET 10's native Swift interop via the SwiftBindings SDK.

License

The bindings are MIT licensed. CryptoKit is part of the Apple SDK; refer to Apple's licensing for the underlying framework.