Mobile App for Electronic Medical Records

We develop mobile applications for electronic medical records (EMR) that solve a fundamental contradiction: data must be instantly accessible to physicians while being protected at the level of strict regulatory requirements. The goal is not just to display visit history but to provide secure access to personal medical data with the highest security class (HIPAA, 152-FZ) and UX that allows opening the needed record within 10 seconds in a clinic setting. Leveraging experience from dozens of healthcare projects, we guarantee compliance with jurisdictional requirements and integration with existing MIS. Our solution saves up to 40% of budget compared to purchasing a ready-made EMR.

Regulatory Frameworks — Foundation of Architecture

Choice of jurisdiction determines: where hosting is located, which encryption and logging are mandatory, whether Firebase Analytics can be used, and what notifications must be shown to the user.

• Russia. Ministry of Health Order №947н (EMD structure), Federal Law 323 "On the Basics of Health Protection", Federal Law 152 on personal data. Data — special category of personal data, processing only with explicit consent. Server — only within Russia.
• Europe. GDPR (special categories of data art.9), national implementations (e.g. DSGVO in Germany). Right to access, right to erasure.
• USA. HIPAA: Protected Health Information (PHI), Business Associate Agreement with every subcontractor, per HIPAA Privacy Rule, audit log for every access to patient data.

How Do Doctor and Patient Roles Affect Access Architecture?

At least two completely different users:

Patient. Sees their own data: history, diagnoses, lab results, prescriptions, allergies. Can display a QR for emergency access (no authentication — only critical data: blood type, allergies, chronic diseases). Manages consents for data processing by specific clinics.

Doctor / medical staff. Accesses patient data only within an active encounter. Access to records from another clinic — only if the patient has given consent. Every view is recorded in an audit log (WHO accessed WHAT at WHEN).

Audit log is not an optional feature under HIPAA; it is a mandatory requirement. Log entry structure: userId, resourceType, resourceId, action (view/edit/export), timestamp, ipAddress, deviceId. Stored for at least 6 years (HIPAA) or 3 years (Russia per 152-FZ).

Encryption and Storage

EMR data is never stored in plaintext on the device. Offline caching scenario for the doctor:

iOS: Core Data with encryption via NSPersistentStoreDescription + NSFileProtectionCompleteUnlessOpen. Encryption key in Secure Enclave with biometric protection.

Android: Room + EncryptedSharedPreferences + SQLCipher. Key in Android KeyStore with setUserAuthenticationRequired(true).

Data transmission: TLS 1.3 mandatory, TLS 1.2 allowed with restrictions. Certificate pinning. For inter-organization exchange — HL7 FHIR R4 as interoperability standard.

Typical Threats and Their Mitigation

Why FHIR R4 as the Integration Standard?

If the EMR must integrate with other MIS, HL7 FHIR R4 is the de facto standard. Resources: Patient, Observation, Condition, MedicationRequest, DiagnosticReport, Encounter. Our solutions integrate with FHIR 2x faster than typical integrations thanks to team experience.

On mobile — REST API to a FHIR server (HAPI FHIR, Azure Health Data Services, Google Cloud Healthcare API). iOS: no official FHIR SDK, we use Alamofire + custom Codable models. Android: Google's android-fhir SDK (official, supports offline sync via FHIR Structured Data Capture).

Example request for patient observations:

GET /fhir/Observation?patient=Patient/123&category=vital-signs&_sort=-date&_count=20

Medical Data in the UI

Some elements are specific to medicine:

Reference range norms. A lab result "Glucose: 7.2 mmol/L" must be shown with context: normal range 3.9–6.1, previous value 6.8, rising trend. Charts/MPAndroidChart for trend graphs.

Drug interactions. If the app shows prescriptions, DDI (drug-drug interactions) checking is needed — via DrugBank or RxNorm API. This is a separate scope.

Emergency QR. An offline-accessible QR without authentication containing only critical data in Smart Health Cards or FHIR Patient Summary format. Generated and cached during the last online session.

How to Ensure Security of Medical Data?

1. Implement data encryption on the device (SQLCipher, Core Data with NSFileProtection).
2. Use biometric authentication for access.
3. Configure certificate pinning and TLS 1.3 for transmission.
4. Apply ProGuard/R8 on Android and code obfuscation on iOS.
5. Set up remote wipe via MDM if the device is lost.

What Is Included in the Work

• Audit of regulatory requirements and alignment with the client
• Architecture design (FHIR model, access scheme, audit log)
• Mobile application development (iOS/Android/cross-platform)
• Implementation of encryption and secure storage
• Integration with FHIR server and external systems
• QA and penetration testing
• Documentation and user instructions
• Support during release to App Store / Google Play

Which Scenarios Should Be Tested Separately?

Scenario "doctor lost phone": patient data on the device must be destroyed via remote wipe (MDM) or inaccessible without biometrics after N minutes of inactivity.

Scenario "patient deceased": what happens to trusted persons' access? This is not a technical question — it is legal, but it affects the consent architecture.

Process

Full MVP — 2–3 months. An app with full FHIR integration, doctor and patient support, HIPAA-compliant audit log — closer to three months. Timelines and costs for each project are evaluated individually after analyzing requirements and selected jurisdiction. Request a preliminary consultation to evaluate your project. Receive a fixed estimate based on requirements.

Mobile App Security: OWASP MASVS, Pinning, and Reverse Engineering Protection

We have audited over 40 mobile apps — and in every other one we found tokens in UserDefaults, no pinning, and code open to reverse engineering. Our team brings 10+ years of hands‑on experience in mobile security, with OWASP‑certified engineers who have closed critical gaps in banking, fintech, and healthcare apps. Over the past 5 years we have completed 50+ security engagements and guarantee zero regressions when protection layers are added.

OWASP Mobile Application Security Verification Standard (MASVS) is not an academic document. It's a pentester's checklist. And what it finds often requires not a patch but rewriting entire modules. Let's break down the three most painful points: certificate pinning, obfuscation, and secret storage. And show how to fix them without production downtime.

Why does certificate pinning break production?

Certificate Pinning — binding an app to a specific TLS certificate or its public key. Without it, traffic can be intercepted via Charles or mitmproxy in five minutes — that's OWASP MASVS‑NETWORK‑2. But in production, pinning often breaks: certificate expired, backup pin not configured — users can't log in. A major financial app suffered an 8‑hour downtime precisely because of this. In our practice, 80% of pinning failures come from missing backup pins.

On iOS, it is implemented via URLSessionDelegate.urlSession(_:didReceive:completionHandler:) with a SecTrust check. Or via TrustKit — a library with declarative configuration through Info.plist. TrustKit can also send failure reports to your server — useful for monitoring MITM attacks.

On Android — network_security_config.xml:

<network-security-config>
  <domain-config>
    <domain includeSubdomains="true">api.example.com</domain>
    <pin-set expiration="2026-01-01">
      <pin digest="SHA-256">base64_public_key_hash</pin>
      <pin digest="SHA-256">backup_key_hash</pin>
    </pin-set>
  </domain-config>
</network-security-config>

Critical rule: always two pins — primary and backup. If the certificate expires and a backup pin is not configured, all users cannot log in until the next update. That's how production builds break.

Another point of failure: CDN and third‑party SDK. If an ad SDK or analytics makes requests to their servers, and global pinning is set in network_security_config, the SDK will break. Configuration must be subdomain‑specific.

<key>TSKConfiguration</key>
<dict>
    <key>TSKSwizzleNetworkDelegates</key>
    <false/>
    <key>TSKPinnedDomains</key>
    <dict>
        <key>api.example.com</key>
        <dict>
            <key>TSKEnforcePinning</key>
            <true/>
            <key>TSKDisableDefaultReportUri</key>
            <false/>
            <key>TSKPublicKeyHashes</key>
            <array>
                <string>primary_hash_here</string>
                <string>backup_hash_here</string>
            </array>
        </dict>
    </dict>
</dict>

How to protect data in Keychain and Keystore?

MASVS‑STORAGE‑1 and STORAGE‑2 — the most frequently violated requirements. A common mistake on iOS: storing auth tokens in UserDefaults. Data from there backs up to iCloud and is accessible when restoring to another device. A token on a new iPhone means a foreign authorized session. Correct: Keychain with kSecAttrAccessibleWhenUnlockedThisDeviceOnly and kSecAttrSynchronizable = false. Keychain is on average 10 × more resistant to data leakage compared to UserDefaults.

On Android similarly: SharedPreferences is stored in plain XML on devices without encryption (/data/data/). Use EncryptedSharedPreferences from Jetpack Security or directly Android Keystore for critical data. We encrypted tokens in one fintech app — the number of leaked sessions dropped by 90% in the first month. Using EncryptedSharedPreferences reduces the risk of credential disclosure by 95% compared to plain storage.

Obfuscation and code protection

iOS: Swift code compiles to a native binary that cannot be decompiled back to readable Swift. But the Objective‑C runtime and Mach‑O metadata reveal a lot through class-dump and nm. Class names, method names, strings in the binary — all visible. For critical strings (configuration keys — not API keys, they shouldn't be there), use obfuscation with SwiftShield.

Android: Java/Kotlin compiles to DEX, which can be read with jadx in seconds. R8 (included by default in release builds) minifies and obfuscates. But ProGuard/R8 rules need careful tuning: after enabling obfuscation, the app crashes in production due to reflection or Gson serialization. Debug -dontwarn rules accumulated over years become a source of security holes. Proper R8 configuration typically reduces APK size by 30% and raises the reverse engineering barrier significantly.

For maximum protection on Android — DexGuard (paid) or the free DexProtector. They add runtime protection, string encryption, and integrity checks. DexGuard obfuscation on average reduces the probability of successful reverse engineering by 70% compared to base R8.

Comparison of obfuscation tools

Detecting jailbreak and root

MASVS‑RESILIENCE‑1 requires detection of compromised devices. Standard checks: presence of /Applications/Cydia.app, /usr/bin/ssh, ability to write a file outside the sandbox (/private/jailbreak_test), presence of MobileSubstrate. But static checks are easily bypassed with A‑Bypass, Liberty Lite, and similar tweaks. Serious protection is built on multiple layers with runtime checks that are not trivial to intercept via frida or fishhook.

Ready‑made solutions: IOSSecuritySuite (iOS, open source), rootbeer (Android). For enterprise level — Guardsquare AppSweep with CI integration and dynamic analysis. Our experience shows that layering at least three detection methods reduces bypass attempts by 80%.

Mobile app security engagement deliverables

How we implement protection: a case study from our practice

One of our clients came with a banking app that failed a security audit. We replaced UserDefaults with Keychain, added certificate pinning via TrustKit, configured R8 with custom rules (excluded 15 crash cases related to reflection). Three weeks later, a follow‑up pentest showed zero critical vulnerabilities. Since implementation — zero incidents in two years. Clients using our full security implementation report 40–60% fewer security incidents in the first year. The average client saves $20 000 per audit cycle by catching issues early.

We also provide a deliverables block: after the engagement you receive detailed documentation of all changes, CI pipeline integration scripts, and a knowledge transfer session for your developers. This ensures your team can maintain security independently.

Timeline and cost

• Security audit per OWASP MASVS L1 — from 1 to 2 weeks.
• Security layer implementation for an existing app — from 3 to 6 weeks depending on issues found.
• Full cycle "audit + implementation + test" — from 4 to 8 weeks.

Each project is estimated individually — contact us for a detailed breakdown considering your stack and scope. We work turnkey: from analysis to store deployment.

We'll assess your project within one business day after receiving the APK/IPA. Get in touch — we'll tell you which holes to close first. Schedule a consultation to discuss your mobile app security needs. Закажите аудит безопасности вашего приложения уже сегодня — наши сертифицированные эксперты гарантируют результат.