# Device Integrity

Verify device legitimacy and app integrity using DeviceCheck (DCDevice per-device bits)...

- Repository: https://github.com/dpearson2699/swift-ios-skills (1266 stars)
- Category: Engineering
- License: see repository
- Last updated: 2026-07-31
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add dpearson2699/swift-ios-skills --skill device-integrity -g -a claude-code -y`
Codex: `npx skills add dpearson2699/swift-ios-skills --skill device-integrity -g -a codex -y`
Cursor: `npx skills add dpearson2699/swift-ios-skills --skill device-integrity -g -a cursor -y`
Gemini CLI: `npx skills add dpearson2699/swift-ios-skills --skill device-integrity -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add dpearson2699/swift-ios-skills`

## Description

Verify device legitimacy and app integrity using DeviceCheck (DCDevice per-device bits) and App Attest (DCAppAttestService key generation, attestation, and assertion flows). Use when implementing fraud prevention, detecting compromised devices, validating app authenticity with Apple's servers, protecting sensitive API endpoints with attested requests, or adding device verification to a backend architecture.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Device Integrity

Verify that requests to your server come from a genuine Apple device running a
legitimate instance of your app. DeviceCheck provides per-device bits for
simple flags (e.g., "claimed promo offer"). App Attest uses Secure Enclave keys
and Apple attestation to cryptographically prove app legitimacy on sensitive
requests.

## Contents

- [DCDevice (DeviceCheck Tokens)](#dcdevice-devicecheck-tokens)
- [DCAppAttestService (App Attest)](#dcappattestservice-app-attest)
- [App Attest Key Generation](#app-attest-key-generation)
- [App Attest Attestation Flow](#app-attest-attestation-flow)
- [App Attest Assertion Flow](#app-attest-assertion-flow)
- [Server Verification Guidance](#server-verification-guidance)
- [Error Handling](#error-handling)
- [Common Patterns](#common-patterns)
- [Common Mistakes](#common-mistakes)
- [Review Checklist](#review-checklist)
- [References](#references)

## DCDevice (DeviceCheck Tokens)

[`DCDevice`](https://sosumi.ai/documentation/devicecheck/dcdevice) generates a
unique, ephemeral token that identifies a device. Treat each token as
single-use: generate a new token for each server operation instead of caching or
reusing one. The token is sent to your server, which then communicates with
Apple's servers to read or set two per-device bits. Available on iOS 11+.

### Token Generation

```swift
import DeviceCheck

func generateDeviceToken() async throws -> Data {
    guard DCDevice.current.isSupported else {
        throw DeviceIntegrityError.deviceCheckUnsupported
    }

    return try await DCDevice.current.generateToken()
}
```

### Sending the Token to Your Server

```swift
func sendTokenToServer(_ token: Data) async throws {
    let tokenString = token.base64EncodedString()

The rest: https://github.com/dpearson2699/swift-ios-skills/blob/HEAD/skills/device-integrity/SKILL.md