A signature verifies the author of the app and ensures the code hasn't been tampered with since it was signed.
In the Android ecosystem, every application must be digitally signed with a certificate before it can be installed. Download Idle Island City Idle Tycoon Mod Signed apk
An "unsigned" APK cannot be installed on a standard Android device without developer workarounds. A "signed" mod APK allows for a standard installation experience, though it will still be flagged as being from an "Unknown Source". Gameplay Mechanics of Idle Island A signature verifies the author of the app
Official versions from the Google Play Store use the developer's private key. A Mod APK is a version modified by a third party to add features like unlimited money. Because the third party doesn't have the original developer's key, they must "re-sign" it with their own certificate. A "signed" mod APK allows for a standard
Idle Island - City Idle Tycoon is a simulation game where players build houses, stores, and banks to grow a private island empire. Idle Island - City Idle Tycoon – Apps on Google Play