Securing Mobile App REST APIs: JWT Authentication, Token Refreshing & SSL Pinning

Why Basic HTTPS Is No Longer Enough

Attackers can install custom CA certificates on rooted Android or jailbroken iOS devices and inspect decrypted API traffic using tools like Charles Proxy or Burp Suite. If your app transmits confidential customer financial data, you must enforce SSL Certificate Pinning.

Defense-in-Depth Mobile Architecture

• Public Key Pinning: The app hardcodes the SHA-256 hash of the server's public key certificate, terminating any connection that presents a mismatched certificate.
• Short-Lived Access Tokens: JWT access tokens expire after 15 minutes. Secure HTTP-only refresh tokens stored in iOS Keychain / Android KeyStore fetch new access tokens automatically.
• Root & Jailbreak Detection: Detect compromised runtime environments and disable sensitive financial transactions to prevent memory inspection.