Technology September 30, 2020 Last updated September 30th, 2020 1,785 Reads share

Best Practices for Secure iOS App Development

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Smartphone apps contain a lot of confidential data like banking details, location data, home address, contact details, health information, and personal ID cards. So, losing this sensitive information or getting hacked can have serious implications. App developers can leverage the following best practices for designing apps that ensure complete data security against thefts and leaks.

1. Apple’s App Sandbox

Apple’s App Sandbox is enabled with UNIX to ensure that everything outside the home directory is set-up as read-only and all the system resources remain protected at all times. The APIs keep the apps from escalating privileges to modify iOS or other apps.

This app needs to declare exclusive privileges for performing certain operations and these outstanding entitlements are signed along with the app, so they cannot be modified. Audio input, CarPlay and HealthKit are a few examples of services that need exclusive entitlements for secure access and use.

Apart from special entitlements, apps can also use iOS extensions to give special rights. The OS has several points that can be used by extensions that are bundled with the app. These extensions run in their separate address space but are controlled by the OS.

Plus, iOS offers several ways to avert security bugs. Address space layout randomization assigns random regions for storage memory in every app for every startup, eliminating the possibility of exploitation by corruption bugs.

Additionally, memory pages that are marked with ARM’s Execute Never are non-executable and have the ability to block the implementation of malicious codes.

2. Native SSL Libraries and Certificate Pinning

Always use native SSL libraries instead of third party libraries as they are vulnerable to exploitation and are at an increased risk of man-in-the-middle attacks. You can use Mutual SSL authentication to validate server connection and to ensure that your app is communicating directly to the right server.

HTTPS connections are validated by default and so, the system checks the server certification and domain validity. However, attackers can still execute complex attacks. To prevent these attacks, iOS apps can integrate additional trust verification of server certificates using certificate pinning.

SSL pinning can be easily implemented by integrating valid certifications in the app bundle. With certificate pinning, the app can check if the certificate in use is on the list and only then establish a connection with the server.

3. End-to-End File Encryption

End-to-end encryption allows you to secure messages in a manner that only the sender and the recipient can decrypt the conversation and neither the servers nor Apple can read the cleartext information.

Encryption is not easy to execute and so, it needs in-depth experience and expertise in cryptographic processes. If an inhouse expert is not available, it is recommended to consult a third-party specialist for help with the implementation of end-to-end encryption.

4. Keychain

All iOS apps should leverage the inbuilt security of KeyChain to store sensitive credentials, passwords along with small chunks of confidential information. This hardware-accelerated storage space encrypts all the content and only app developers have access to this space.

The keychain is a secure storage option for NSUserDefaults that have no encryption and should not be used for confidential information. For each keychain item, developers can define exclusive authentication policies for secure access. It can include Face ID, Touch ID or a biometric ID.

Additional functionality of the Keychain is the ability to decide where to store the data in – the local keychain or in the iCloud, which can then be synced across all Apple gadgets.

5. CloudKit

Apple’s Cloudkit is an ideal solution for apps that don’t need a server. CloudKit stores information in iCloud containers so users can use their Apple ID to login to the app. This way, developers don’t need to implement any particular service or login mechanism separately.

Security is at the core of CloudKit and communication is by default encrypted. All the communication between the app and the server can be exchanged on the CloudKit platform. And, even in case of an additional web app, the CloudKit can still be used with its web services and JavaScript.

To take this experience to the next level, CloudKit is free to use up to a specific limit. CloudKit gives you easy access to millions of users without inviting any cost on data storage, traffic or requests.

6. Cryptographic API

The iOS SDK uses API keys for managing standard cryptographic processes. However, it is recommended to use only proven crypto implementations for this purpose instead of reimplementing them from scratch.

Apple’s CryptoKit was recently introduced in iOS 13 to allow low-level APIs to implement security protocols and to perform cryptographic tasks. With CryptoKit, you can also use the SecureEnclave for implementing safe functions to optimize the hardware of the device.


Creating a secure iOS app is challenging, but there are tried and tested ways to make the apps more robust and reliable against attackers. You can follow the practices mentioned above while avoiding common risks like weak encryption, unreliable hosting controls, device fragmentation, insecure data storage frameworks and malicious third-party libraries.

In general, you can use this essential checklist to ensure that all the points are ticked off:

  • Write a secure code that cannot be reverse-engineered
  • Ensure that the data cannot be decrypted
  • Avoid using third-party libraries that you cannot rely on 100%
  • Use only authorized APIs
  • Use a high-level authentication mechanism
  • Have a tamper detection technology in place
  • Store confidential data in the Keychain
  • Use HTTPs for facilitating communication between client and server
  • Do not use third-party SDKs

Even if you follow all of these tips, be sure to have an expert validate your iPhone mobile development approach to be 100% sure. Businesses must ensure that their mobile app strategy is carefully crafted and well designed to avoid unwanted consequences due to lack of security.

Delivering a user-friendly and security-compliant app will not only ensure the security of enterprise and consumer data but also enhance brand identity. The best way to go about this is by consulting an expert iPhone mobile development company with vast experience in deploying seamless and secure mobile apps for businesses across verticals, including retail, healthcare and finance.

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Ryan Williamson

Ryan Williamson

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