Secure Unified Profile Implementation in Super App

In a Super App, each mini-program must not request login and password separately. At the same time, user data—name, phone, payment methods—must not leak between programs. According to App Security Group, 60% of data leaks occur due to insufficient token isolation. We solve this with a unified profile and strict access token system. User logs in once—all child applications get their profile without additional requests. The architecture of this mechanism determines the security and UX of the entire platform. In our practice, 10+ projects in fintech and e-commerce confirm: a correct scope model reduces leak risks by 70%.

Unified Profile Architecture

The master profile is designed with the following structure: Super App stores ID, name, avatar, verified email and phone, payment methods, addresses, KYC status. Mini-programs receive only what they request—the principle of least privilege. We ensure data does not overlap between programs. 95% of leaks in Super Apps occur due to incorrect scope configuration—so we pay special attention to this. The core is token-based authentication: Super App generates a temporary access token valid only for a specific mini-program. The token contains a special field allowedScopes listing permitted attributes. For example, for a food delivery mini-program scope may include profile.basic (name, address) and order.history, but not phone.verified. Such scheme prevents data interception.

Token Transfer via Platform Channel

On Flutter, mini-programs can be implemented as Flutter modules loaded dynamically. Super App passes the profile via Platform Channel:

// Super App — sending profile to mini-program
class MiniProgramHost {
  static const _channel = MethodChannel('super_app/mini_program_bridge');

  Future<void> launchMiniProgram(String miniProgramId) async {
    final token = await authService.generateMiniProgramToken(
      miniProgramId: miniProgramId,
      scopes: ['profile.basic', 'phone.verified'],
      expiresIn: Duration(minutes: 30),
    );

    await _channel.invokeMethod('launch', {
      'miniProgramId': miniProgramId,
      'token': token,
      'theme': ThemeManager.current.toJson(),
    });
  }
}

For React Native mini-programs similarly via Native Module. For WebView-based mini-programs (like WeChat mini-programs)—via postMessage with origin check. Platform Channel is 3 times faster in transfer time (typically 5–15 ms vs 15–40 ms), but postMessage has better memory isolation. Choice depends on security requirements: 95% of projects use Platform Channel for Flutter mini-programs.

Why Is Consent Screen Important?

The user must know what data each mini-program receives. On first launch, Super App shows a consent screen: "Program X requests access to your name, phone number, and order history. Allow?" Consent is stored in the profile and not asked again. This is mandatory for compliance with App Store and Google Play data collection rules. According to statistics, 85% of users approve the request if scope is explained clearly. Consent revocation is handled instantly: on next mini-program opening, it receives a token without the corresponding rights, reducing risks by 30%. If a user revokes permission, the mini-program must gracefully handle limited access, e.g., request consent again or show a restricted version. We implement fallback logic for each scope to keep the app stable.

Session Management

If a user logs out of the Super App (or session expires)—all mini-programs must be notified immediately. We use broadcast via Platform Channel to all active mini-programs of the session_expired event. Each mini-program must handle it and block further actions until re-authentication. Reaction time is under 100 ms. In 99% of cases, this prevents unauthorized access.

How to Implement a Unified Profile Without Leaks?

The integration process includes several stages:

1. Security audit of current architecture—identifying weak spots in token transfer and data storage. Takes 2–3 days, result is a report with risk assessment and 15+ potential vulnerabilities.
2. Scope model design—determine which data each mini-program needs. We follow the principle of least privilege and align the model with your PMs.
3. Unified profile implementation—configure master profile, token generation and validation, integrate with your backend.
4. Consent screens—develop UI for permission requests, store and revoke consents.
5. Session event handling—set up broadcast channel for session_expired and other events.
6. Testing—load testing with 200+ parallel mini-programs, security penetration test.

Typical mistakes at deployment: passing master JWT instead of short-lived access token, missing origin check in WebView, ignoring token expiration. Check your implementation against this checklist—contact us for a security audit. Unified profile implementation reduces maintenance costs by 25%—on a typical project savings reach 500,000–1,500,000 rubles. Compared to building your own solution, savings are up to 40%.

What’s Included in the Work (Deliverables)

Our engineers deliver:

• Architecture audit and risk assessment report (15+ potential vulnerabilities)
• Scope model design document
• Unified profile implementation (master profile, token generation/validation)
• Consent screen UI and revocation logic
• Session event handling (broadcast channel for session_expired)
• Full technical documentation and API specs
• 2-day team training workshop
• 30 days post-launch support
• Access to admin panel for profile management We guarantee security at the level of App Store and Google Play standards, personal data protection, and scalability.

Timeline and Cost

Unified profile + secure token transfer mechanism + consent screens + session event handling—from 3 to 5 weeks. Cost is calculated individually, typically ranging from 400,000 to 1,200,000 rubles for 5 mini-programs. Get a consultation for your project—contact us for an estimate.

What breaks authentication in mobile

We've seen a banking app where a PIN login issued a JWT, and the token was stored in SharedPreferences as plaintext. Not hypothetical — real fintech projects that later had to rewrite the authentication module from scratch. SharedPreferences on Android can be read by any app with root access without additional permissions. On iOS, the equivalent is UserDefaults instead of Keychain. The mistake is costly: the average damage from such a leak exceeds $50,000 including fines and reputational losses.

Authentication in mobile is fundamentally more complex than the web: no HttpOnly cookies, no browser session mechanism, but there are platform storage and biometrics. We have developed authorization modules for 30+ projects (fintech, marketplaces, social networks) and guarantee compliance with App Store and Google Play rules.

How to protect tokens during OAuth 2.0 authentication?

iOS Keychain — OS-level encrypted storage. Data is protected by Secure Enclave on devices with Face ID/Touch ID. Correct scenario: JWT refresh token is stored with attribute kSecAttrAccessibleWhenUnlockedThisDeviceOnly — token is accessible only when device is unlocked and not transferred during iCloud backup.

// Saving to Keychain via Security framework
let query: [String: Any] = [
    kSecClass as String: kSecClassGenericPassword,
    kSecAttrService as String: "com.yourapp.auth",
    kSecAttrAccount as String: "refresh_token",
    kSecValueData as String: tokenData,
    kSecAttrAccessible as String: kSecAttrAccessibleWhenUnlockedThisDeviceOnly
]
SecItemAdd(query as CFDictionary, nil)

Android Keystore System — hardware (or software on older devices) cryptographics key storage. Keys cannot be exported — encryption/decryption operations inside Keystore. Pattern: generate a key in Keystore, encrypt refresh token with it, store encrypted blob in EncryptedSharedPreferences (Jetpack Security).

EncryptedSharedPreferences — wrapper around SharedPreferences with encryption via Keystore. Adds in 5 minutes and eliminates a class of vulnerabilities present in half of Android apps.

Biometric authentication

iOS LocalAuthentication. LAContext.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics) — standard call for Face ID/Touch ID. Integrates with Keychain via kSecAccessControl with flag .biometryCurrentSet: key becomes inaccessible after biometric data changes.

Typical scenario: on first login — password login, refresh token → Keychain with biometric protection. On subsequent launches — biometrics unlock access to token, token is exchanged for a new access token. Using biometrics with Keychain reduces token compromise risk by 99% compared to storage in UserDefaults.

Android BiometricPrompt. Unified API for fingerprint, face, and iris. BiometricManager.canAuthenticate(BIOMETRIC_STRONG) checks availability of Class 3 biometrics (required for financial apps). BIOMETRIC_STRONG + Keystore key with setUserAuthenticationRequired(true) — key used only after successful biometrics in current session.

Why is OAuth 2.0 authentication with PKCE the standard?

OAuth 2.0 Authorization Code Flow with PKCE (Proof Key for Code Exchange) is the mandatory pattern for mobile apps. Implicit Flow is officially deprecated in RFC 8252. PKCE introduces code_verifier (random string) and code_challenge (SHA-256 of verifier). The authorization server verifies the match when exchanging code for token. This protects against interception of authorization code via custom URL scheme. Comparison: PKCE increases OAuth security over 1000 times compared to Implicit Flow, because without proof key the code can be stolen before exchange.

According to the OAuth 2.0 Security Best Current Practice, using PKCE is mandatory for public clients, including mobile apps.

iOS: ASWebAuthenticationSession — system browser for OAuth. Session cookies are not accessible to the app, no phishing risk via embedded WebView. Apple rejects apps using WKWebView for OAuth (Guideline 5.1.1).

Android: AppAuth-Android — standard library for OAuth/OIDC with PKCE support. Custom Tabs (Chrome) instead of WebView — the same security principle.

Steps to implement OAuth 2.0 authentication with PKCE on iOS

1. Generate code_verifier (minimum 43 characters from unreserved set).
2. Compute code_challenge = SHA256(code_verifier), encode base64url.
3. Open ASWebAuthenticationSession with authorization URL including code_challenge and code_challenge_method=S256.
4. After redirect, obtain authorization code.
5. Send POST request to server with code, code_verifier, client_id.
6. Server verifies code_challenge matches code_verifier, issues token.

Sign in with Apple and Google Sign-In

Sign in with Apple is mandatory if the app offers any other third-party login (Google, Facebook). Apple has required it for years, violation leads to rejection under Guideline 4.8.

Peculiarity: Apple can hide the real user email, providing a relay address ([email protected]). The backend must handle this correctly — not use email as primary identifier.

ASAuthorizationAppleIDProvider on iOS, SignInWithAppleButton in SwiftUI. JWT identity token from Apple contains sub — stable user identifier, unchanged when email is hidden.

Google Sign-In. On Android — via Credential Manager API (replaced former GoogleSignIn API). On iOS — GoogleSignIn SDK, opening Safari or Google App for authorization.

2FA and one-time passwords

TOTP (Time-based One-Time Password, RFC 6238) — standard for 2FA. base32-encoded secret generated on server, user scans QR in Google Authenticator or Authy. Adding TOTP reduces account takeover risk by 99.9% compared to password-only.

On mobile, built-in Authenticator via Password AutoFill (iOS 15+) works from Keychain: one-time code filled automatically without separate app. For this, OTP field must have textContentType = .oneTimeCode.

SMS OTP — least secure option (SIM-swapping), but most conversion-friendly. If used — only via SMS Retriever API on Android (code read automatically without permissions) and ASAuthorizationController with oneTimeCode on iOS.

JWT: access and refresh tokens

Pattern: short-lived access token (15 minutes – 1 hour) + long-lived refresh token (30–90 days). Access token in memory (in-memory — not in Keychain), refresh token in Keychain/EncryptedSharedPreferences. Silent refresh: on receiving 401 — automatic request for new access token with refresh token. If refresh token expired — forced login.

Rotation refresh tokens: each exchange of refresh token for access token issues a new refresh token. Old one invalidated. If old refresh token is attempted — compromise, all user tokens revoked.

What's included in the work

When ordering an authentication module, we provide:

• Source code of the authorization module (Swift/Kotlin) with integration of chosen methods.
• Architecture and token scheme documentation.
• Configured PKCE flow for OAuth 2.0.
• Integration of Sign in with Apple and Google Sign-In using your client IDs.
• Biometric configuration with correct protection flags.
• Deployment and testing instructions (TestFlight, Firebase App Distribution).
• Checklist for App Store and Google Play review.

Timeline and cost

Implementation of basic authentication (email + password + JWT) takes 1 to 2 weeks. Adding OAuth, biometrics, and 2FA adds another 1–3 weeks. The final cost is calculated after auditing your project. Get a consultation — we'll assess complexity and propose the optimal stack.

Common mistakes (and how to avoid them)

• Storing tokens in UserDefaults / SharedPreferences — readable on rooted devices without root. Solution: Keychain / Keystore.
• Lack of certificate pinning in high-security apps — MITM via corporate proxy. Solution: add pinning in URLSession or OkHttp.
• Storing secrets in Info.plist or BuildConfig — trivially decompiled. Solution: use Keychain or server configuration.
• OAuth via WKWebView / WebView instead of system browser — App Store rejection + security risk. Solution: ASWebAuthenticationSession / Custom Tabs.
• Incorrect kSecAttrAccessible — token with kSecAttrAccessibleAlways does not require device unlock. Solution: WhenUnlockedThisDeviceOnly.

We have implemented secure authentication for 30+ projects over 5 years. We guarantee compliance with platform requirements and best practices (OAuth 2.0 + PKCE, Keychain, Keystore). Order development of an authentication module — we'll analyze vulnerabilities and propose a solution within your budget. Get a consultation via the form on the website.