HealthTech API Security: Protecting Patient Data with mTLS and OAuth 2.0

Source: Dev.to

Introduction

In HealthTech, APIs act as the digital arteries of innovation, moving life‑saving data between EHR systems, patient apps, and third‑party services. This connectivity brings immense responsibility: a single vulnerability can expose Protected Health Information (PHI), leading to regulatory penalties and loss of patient trust.

Layered Security Approach

OAuth 2.0 with Granular Scopes

• Grants applications only the specific data they are permitted to access (e.g., “read‑only” for lab results).
• Prevents over‑privileged access where an app could otherwise retrieve an entire patient history.

Mutual TLS (mTLS)

• Requires both server and client to verify each other with certificates.
• Ensures that only trusted machines can initiate a conversation, mitigating stolen‑token attacks from unknown devices.

Rate Limiting

• Controls the number of requests a client can make within a given timeframe.
• Protects infrastructure from accidental overloads or malicious denial‑of‑service (DoS) attacks.

Security Layer Comparison

Implementation Steps

1. Generate keys and certificates – use tools such as OpenSSL to create private keys and X.509 certificates.
2. Configure an API gateway – terminate mTLS connections and validate certificates before requests reach your application logic.
3. Inspect token scopes – add middleware that checks the scopes embedded in OAuth 2.0 tokens to confirm both validity and authorization for the requested patient record.
4. Apply rate‑limiting policies – enforce limits per client, IP address, or API endpoint to keep services stable.

Ongoing Maintenance

• Principle of Least Privilege – grant only the minimum access required for each application.
• Key rotation – regularly update cryptographic keys and certificates to prevent reuse of compromised credentials.
• Audit logging – maintain tamper‑resistant logs of who accessed what data and when, a critical requirement for HIPAA compliance.

Quick Checklist

• Verify the machine – use mTLS to ensure only approved hardware can access data.
• Restrict the scope – never give an app more data access than it strictly needs.
• Limit the flow – employ rate limiting to keep services responsive and secure.

For a deeper dive into code and configuration for these security patterns, read the full report on our official blog.