Apple has beefed up its encryption in its latest mobile operating system. The new system has worried U.S. authorities, who fear it may make it more difficult to obtain data for law enforcement. Despite the new protections, data is still vulnerable in certain circumstances, a Princeton University fellow says. Apple doesn’t make it easy to completely copy all of the data on a device and boot it up using external firmware, which would be an attacker’s first step, he wrote. The best advice is to create a password that is at least a 12-digit random number or a nine-character string of lower-case letters.”]