iOS has a strong security baseline: code signing, sandboxing, App Transport Security, Data Protection and the Secure Enclave are all on by default. That baseline leads many teams to assume the platform covers everything. It doesn't. The platform protects the user from malicious apps very well, but it does much less to protect your backend from a modified copy of your app, a scripted client that impersonates it, or a user who deliberately intercepts their own traffic.

This guide looks at four questions that come up in almost every security review of an iOS app. For each one, the goal is an honest answer: what the technique actually protects against, what it does not, and how to implement it correctly if you decide you need it.

Is SSL Pinning Still Necessary?

Secure Keychain Storage vs UserDefaults

API Request Encryption Beyond HTTPS

Device Attestation, App Attest and Application Integrity

Code samples use Swift 5.9+ with CryptoKit, Security and DeviceCheck.…