# Android Sample: OctetSample

A Jetpack Compose demo of the public SDK surface, built around **two tabs**: **Generate** (produce a proof) and **Verify** (check one on-device with `Octet.verify`). It lives under [`octet-sdk/samples-public/android-sample`](https://github.com/octetproof/octet-sdk/tree/main/samples-public/android-sample). Its proof format is byte-compatible with the iOS build.

## What it does

**Generate.** Pick a region, then watch the proof pipeline run step by step (SDK initialized -> sensors warmed up -> location fixed -> proof generated), with per-step timings and a map of your position. You get back the predicate answer from `sdk.loc.isWithin(...)`, and a result card showing the outcome, a confidence bucket, and the battery the run consumed. Generated proofs are kept in a sample-owned store.

**Verify.** Run `Octet.verify(...)` on any stored or imported proof and read the grouped [on-device checks](/docs/v2.0/concepts/on-device-verification/) (signature, freshness, hardware attestation, and the rest), each with a one-line note on any check that could not run and how to make it run. Pick a region to check the proof's claim against, and see the granularity the proof reveals (nothing finer than its level). Proofs export and import as `.octetproof` files through the Android share and Storage-Access layer.

The Compose UI is driven by a single `SampleViewModel` that owns the SDK lifecycle, the generate pipeline, verify, region selection, and the map location.

## Setup

The SDK activates by **attesting the app instance**. There is no license key to paste. On a real device it uses hardware key attestation and bootstraps its license on first launch. Copy the local config so the sample builds:

```bash
cd samples-public/android-sample
cp local.properties.example local.properties
```

`local.properties` is gitignored. You can optionally set `octet.playIntegrityCloudProjectNumber` (your own Google Cloud project number) to bind the per-proof Play Integrity verdict to that project. It is not required to activate: the bootstrap uses hardware key attestation.

Register the sample's package (`com.octetproof.sample`, or your own) under your Octet account, as described in [Prerequisites](/docs/v2.0/getting-started/prerequisites/), so its attestation resolves to a registered app.

## Build

A standalone Gradle project; the SDK (`com.octetproof:sdk`) resolves from the Octet Maven repository configured in `settings.gradle.kts`:

```bash
./gradlew :app:assembleDebug     # build
./gradlew :app:installDebug      # build + install on a connected device
```

The APK lands at `app/build/outputs/apk/debug/app-debug.apk`. Package: `com.octetproof.sample`.

## Run on a real device

This sample needs a physical device with a hardware-backed keystore. An emulator has no real GNSS, cellular, Wi-Fi, or motion hardware, and cannot attest the device, so it cannot generate proofs.

## Requirements

- Android 11 (API 30)+ on the device
- A hardware-backed keystore (TEE or StrongBox)
- Your package registered under your Octet account

## See also

- [Android Quick Start](/docs/v2.0/getting-started/android-quickstart/). Integrating the SDK from scratch.
- [On-device Verification](/docs/v2.0/concepts/on-device-verification/). What the Verify tab runs.
- [Troubleshooting FAQ](/docs/v2.0/troubleshooting/faq/). What to do when verdicts don't look right.