FBI does not plan to reveal how the San Bernardino iPhone was hacked

According to The Wall Street Journal, the FBI does not plan to reveal how the San Bernardino iPhone was hacked. The Bureau seems to argue that it only knows how to use the phone-hacking tool that it had acquired, but does not know how that tool actually works. It therefore does not have enough information to initiate a White House review that would determine whether the security flaw in the iPhone should be disclosed to Apple. At the same time, Apple seems to be confident that the security flaw will not have a long life and will be eliminated through continuous security improvements to the iPhones. Update: the FBI confirmed that it does ‘not have enough technical information about any vulnerability that would permit any meaningful review’.