Avast Anti-Theft for Android: Restoring PIN
How to restore your PIN for Avast Anti-Theft
For security reasons Anti-Theft does not send your Avast PIN to our servers and there is no master key.
There are two methods to change the Avast PIN for Anti-Theft:
Preferred method allows you to change your PIN directly from the Anti-Theft app with your Google Account credentials.
Alternative method allows you to change your PIN via your Avast Account.