All signing services have a hard time providing working certificates therefore it is really difficult to find not revoked certificates. AltStore is the best solution to install the unc0ver jailbreak on compatible devices. Pwn20wnd recommends AltStore app as the official way to install the latest version of the unc0ver jailbreak.
unc0ver supports most of the devices running iOS 11.0 a newer, this includes iPhones and iPads. If you have a supported device you can use AltStore to install the unc0ver jailbreak. Because you will be using a free Apple certificate unc0ver will be not revoked, and this method will succeed every time when you need it.
AltStore can sign the unc0ver app for seven days using your Apple ID and password. The application works almost like Cydia Impactor, but the difference is that after installing AltStore on your device you need your host computer and iOS device to be connected to the same Wi-Fi network for AltServer to sideload apps.
Install unc0ver jailbreak using AltStore
It is absolutely safe to use your Apple ID and provide the password into this app, but if you are not comfortable entering your actual data you can use a temporary account as well. AltStore can be installed from Windows and Mac on your device. I will show you how to use AltStore to install unc0ver jailbreak on your iPhone.
1. Download the latest version of iTunes for Windows (not from Microsoft Store).
2. Download the newest version of iCloud for Windows from Apple's website.
4. Extract the ZIP file, double-click the "setup.exe" file to begin the installation, and follow the on-screen instructions.
5. Connect your iPhone with a USB to Lightning cable, unlock your device, and if prompted, trust the device.
6. Launch the AltServer application.
7. Click on the AltStore icon from the system tray.
8. Log in with your Apple ID and password when prompted, then click Install.
9. AltStore app icon should be visible from the Home screen, but will not open.
10. Navigate to Settings → General → Device Management.
11. Trust the newly installed certificate named [Your Apple ID].
12. Visit unc0ver.dev in Safari on your iPhone and download the IPA file.
13. Next, tap on Safari’s download manager and then select on the unc0ver.ipa file you just downloaded.
14. Use the Share button at the top right of the interface to send "Copy to AltStore" button and tap on it.
15. AltStore app will now import the unc0ver.ipa file. Provide the same Apple ID and click on Sign In button.
16. After AltStore finishes, your unc0ver jailbreak will be installed on your device.
17. Launch the unc0ver app to jailbreak your device.
2. Extract the downloaded ZIP file and move AltServer to the Applications folder.
3. Open the AltServer application.
4. Click on the AltStore icon from the Menu Bar and Install the Mail Plug-in.
5. Confirm the installation process.
6. Enter your administrator password if prompted, and click OK.
7. Open the Mail app and go to Mail → Preferences.
8. Click on the Manage Plug-ins in the General tab.
9. Click on the checkbox next to AltPlugin.mailbundle, next Apply and Restart Mail button. The Mail app must be always running in the background to sign iOS apps.
10. Open AltServer from the menu bar and select Install AltStore.
11. Log in with your Apple ID and password when prompted, then click Install.
12. AltStore app icon should be visible from the Home screen, but will not open.
13. Navigate to Settings → General → Device Management.
14. Trust the newly installed certificate named [Your Apple ID].
15. Download the latest IPA file of unc0ver from the official webite.
16. Select on the unc0ver.ipa file you just downloaded from the Safari’s download manager.
17. Use the Share button at the top right of the interface to send "Copy to AltStore" button and tap on it.
18. AltStore app will now import the unc0ver.ipa file. Provide the same Apple ID and click on Sign In button.
19. After AltStore finishes, your unc0ver jailbreak will be installed on your device.
20. Return to the home screen to open the unc0ver app.