If anyone or any system claim our possess bitcoin can be doubled definitely it is a scam because bitcoins is the most secure network to do transactions that was invented so users should be more aware regarding these things because getting scam is a terrible thing to happen which is a common thing now in the digital currency world and also a sad thing to see because the main reason for developing bitcoin or any altcoin was to make transactions more secure from criminals but the people who use the system is much corrupted today so even these inventions are much pure and developed with good intentions users get hacked and loose there money due to hackers