Code signing is a security mechanism used in iOS development to ensure that apps and their components are verified and trusted by Apple and end-users. It involves digitally signing executable code, resources, and other files associated with an app using cryptographic signatures. Code signing serves several purposes:
- Verification: Code signing allows Apple and users to verify that an app comes from a known and trusted source. It helps prevent unauthorized or tampered versions of apps from being installed on devices.
- App Integrity: Code signing ensures the integrity of an app’s executable code and resources. If any modifications are made to the app’s files after signing, the cryptographic signature becomes invalid, indicating that the app may have been tampered with.
- App Permissions: Code signing is used to enforce app permissions and entitlements granted to an app by the user. Apps must be signed with the appropriate provisioning profile and certificate to access specific device features and services.
- App Distribution: Code signing is required for distributing apps through the App Store or ad-hoc distribution. Apple verifies the code signature during the app review process to ensure compliance with security standards and guidelines.
To code sign an iOS app, developers use Xcode and obtain a code signing certificate and provisioning profile from the Apple Developer portal. Xcode automatically signs the app bundle with the designated certificate and provisions it with the appropriate entitlements. When the app is installed on a device or distributed through the App Store, the device or operating system verifies the app’s code signature to ensure its authenticity and integrity.
Code signing is a critical aspect of iOS development, ensuring the security, integrity, and trustworthiness of apps distributed on the App Store and installed on users’ devices.
