In phones with uses CRYPT (Gatekeeper mechanism) you cannot delete *.key files - this will not give you access to phone as in previous versions.
Deleting those itself might not but also removing, or preferably modyfying locksetting database should work from what i remember. It may depend on the phone itself as the implemention varies, even on older Android versions but it can still be done.
Regarding read password - due its CRYPT we can crack only PIN and Pattern - alphanumeric passwords are not "effective" way in meaning of time for those since only CPU power can be used
Have you actually tested it on more phones, since this implemention may also be different between vendors and even individual phones, plus can also be hardware dependant.
Listen to Bolo, he knows what he is talking about!
I can also confirm that only PIN/pattern cracking can be done well if Gatekeeper is on. Cracking passwords could be also possible with dictionary attacks, but for those tries to be effective, you need good dictionaries and processing power from weeks/months up to a few years… And pure luck, who knows )
I'm not saying he's wrong. His company sells such service so i assume it works. I'm just curious if he encountered phone where it failed to crack.
I tried cracking my personal phone's pattern running 7.1.1 and with currently known implementafion i failed to do so. On the other hand i'm running custom AOSP based firmware so it might differ, it's there's something wrong with my script. In general, there's very little public info related with cracking gatekeeper SCRYPT hashes.
Public informations which Nikolay gives is… let's say "incomplete" and thats why most of people failed to reconstruct PY script but if you will write your own from scratch you will for sure success … we not tried yet on 7.x. Send your gatekeeper.password.key as well as password, phone model and vendor so I will check if it works on 7.1.1