Add Magistrate to Your iOS App

The Magistrate module sits on top of the Octet Mobile SDK. One call, decide, fetches your policy, makes the location proofs it needs, and returns the engine's signed decision.

This page covers Magistrate 0.1.0 for iOS, which needs Octet SDK 3.1.2. See the Changelog for what each release changes.

Prerequisites

• iOS 16 or later, Swift 5.9 or later.
• The Octet Mobile SDK set up in your app, with the App Attest capability and the location and motion usage descriptions in Info.plist. Follow the iOS Quickstart first.
• Your app registered on your Octet license. The SDK signs in with hardware attestation, so there's no license key to paste.
• A policy published from the Magistrate Studio.

1. Add the packages

Add both Swift packages to your app. Swift Package Manager doesn't pass the Octet SDK through Magistrate, so your app adds it as well. Pin it to exactly the version this Magistrate release uses, 3.1.2.

dependencies: [
    .package(url: "https://github.com/octetproof/octet-magistrate-ios", exact: "0.1.0"),
    .package(url: "https://github.com/octetproof/octet-sdk-ios", exact: "3.1.2"),
],
targets: [
    .target(name: "YourApp", dependencies: [
        .product(name: "Magistrate", package: "octet-magistrate-ios"),
        .product(name: "OctetSDK", package: "octet-sdk-ios"),
    ]),
]

Magistrate ships as a precompiled xcframework. Octet SDK 3.1.2 is a dynamic framework, which Xcode embeds and signs with your app.

2. Start the SDK and wrap it

import OctetSDK
import Magistrate

let sdk = try await Octet.start(config: OctetConfig())
let magistrate = Magistrate(sdk: sdk)

To keep the verified policy across launches, pass a store:

let magistrate = Magistrate(sdk: sdk, persistentStore: KeychainPolicyBundleStore())

3. Ask for a decision

Call decide when the user does something your policy protects, such as opening an account or placing a bet.

guard let license = sdk.licenseStatus else { return }   // activation didn't complete

do {
    let result = try await magistrate.decide(license: license)
    if result.cause != nil {
        // UNKNOWN: the location couldn't be settled, for example no fix yet.
        // Ask the user to retry.
    }
    // Send result.receipt to your backend with the request.
    // Your backend verifies it and decides what happens.
    try await api.submit(order, decisionReceipt: result.receipt)
} catch let error as PolicyError {
    // No decision was made. Treat it as NO.
}

decide runs the whole exchange: it fetches the policy, checks Octet's signature on it, gets a one-time challenge, has the SDK make the proofs, and sends them to the engine. Don't manage the challenge yourself, unless your backend starts the check (see Start the check from your backend).

A deny is a result, not an error. result.isPermit is false and result.reasons says why. When result.cause is set, the answer is UNKNOWN: the proofs couldn't settle the location. A PolicyError means no decision was made at all. See Decision Response to read a result as YES, NO or UNKNOWN.

Several policies in one check

decideMany decides 1 to 16 policies with one set of proofs. The device proves once, and the engine decides each policy from the same proofs. Each result carries its policy's name, and forPolicy(_:) looks one up.

let set = try await magistrate.decideMany(license: license,
                                          policies: ["p_…", "p_…"])
for decision in set.results {
    print(decision.policy, decision.decision)
}
let one = set.forPolicy("p_…")

Lower-level calls

Most apps only need decide. Two building blocks are public as well:

func prove(license: LicenseStatus, nonce: String) async throws -> [PolicyProof]
func evaluate(license: LicenseStatus, decisionRef: String) async throws -> PolicyEvaluation

prove makes the location proofs the policy needs, bound to a nonce. Your backend uses it to start the check itself, together with attestationEnrolment() and challengeEnv(license:). evaluate reports a verdict for each region of the policy (PolicyRegionResult), without asking the engine for a decision.

Obligations

A policy can attach obligations to a permit, for example a step-up authentication. A permit with obligations counts only once your app and backend have fulfilled every one. Treat an obligation you don't recognise as NO. See Decision Response.

Things to know

• The first check after start. Location takes a moment to warm up after Octet.start. The first check can come back UNKNOWN, with cause absence. Retry after a few seconds.
• Real devices for production. Production needs hardware attestation on a real device. A simulator or a debug build signs in with a sandbox token (see the iOS Quickstart), and its results and receipts say env sandbox. Your backend accepts only release in production. Checks from a sandbox build also need a sandbox app registered on your license.
• When the policy can't be refreshed. Magistrate falls back to the last policy bundle it verified, but only for the same bundle URL, and only while that bundle still verifies against your license's current keys.
• Geofence policies. A policy with a disc needs an Octet SDK release that can prove one. Until then decide throws bindingUnavailable for it. Policies from the Magistrate Studio don't use discs.
• Errors. See Errors for each PolicyError case.

Verify the download

The package's binaryTarget pins the xcframework by checksum, so Swift Package Manager refuses a zip that differs from the released one. Each release also attaches SHASUMS256.txt, its Sigstore bundle SHASUMS256.txt.sigstore.json, a CycloneDX SBOM and the third-party notices.

The sign-release.yml workflow in the octet-magistrate-ios repository signs SHASUMS256.txt with Sigstore keyless signing when a release is published, so the signing certificate names that workflow and the exact release tag.

To check a release yourself, download its assets into one folder and run these commands with cosign 2.x:

V=0.1.0
IDENTITY="https://github.com/octetproof/octet-magistrate-ios/.github/workflows/sign-release.yml@refs/tags/$V"
cosign verify-blob --bundle SHASUMS256.txt.sigstore.json \
  --certificate-identity "$IDENTITY" \
  --certificate-oidc-issuer https://token.actions.githubusercontent.com \
  SHASUMS256.txt                 # must print "Verified OK"
shasum -a 256 -c SHASUMS256.txt  # every file must print "OK"

A signature from any other workflow, repository or tag fails the cosign step.

Security

Report a vulnerability privately to security@octetproof.com. Bug reports and questions are welcome as issues in the octet-magistrate-ios repository.

Sample app

The sample app starts the SDK, calls decide and shows the decision, reasons and obligations. It needs a real device.

License

Magistrate is licensed under the Octet SDK License Agreement.