FBI bought $1m iPhone 5C hack, but doesn't know how it works

US law enforcement agency in possession of mechanism for unlocking iPhone 5Cs or older - but identity of hackers closely guarded secret

The FBI doesn't know how the hack used to unlock the San Bernardino shooter's iPhone 5C works, and yet it paid in the region of $1m for the mechanism, which can used again to unlock any other iPhone 5C running iOS 9, according to reports.

Several US government sources told Reuters that the amount paid for the hack, bought from professional hackers, was substantially less than previous reports indicating a value over $1.3m. The technique can also be used as many times as needed without further payments.