If you have enabled iCloud Keychain on your iOS device, then the pin from iBridge 3 app will sync to the keychain on all devices with same Apple ID. So you would be able to see the pin from Keychain on Mac. You will only need to enter administrator's password. Here is how you can do that.
If you did not have a Keychain on your iOS device, then there is no way to retrieve or reset password on locked drive.