Cydia Impactor

Cydia Impactor is a multifunction tool available for Windows, Mac, and Linux, created by Jay Freeman (saurik), used to install IPA files on iOS and APK files on Android. It is able to exploit the series of Android "Master Key" vulnerabilities.

Apps installed with Cydia Impactor are signed for seven days using a free developer account associated with any Apple ID, or one year if the user has a paid developer account.

Cydia Impactor has been used to accomplish semi-untethered jailbreaks on iOS devices in recent years - specifically, it is used to sideload the IPAs that are then used to jailbreak, such as Pangu9 for iOS 9.2-9.3.3, Home Depot, yalu, PPJailbreak for iOS 10 and LiberTV.

A note about Cydia Eraser
Cydia Eraser, a tool similar to SemiRestore that can be used to wipe the device and preserve the iOS version, was previously called Cydia Impactor. However, saurik chose to change the name to Cydia Eraser to prevent confusion.