Leaks in general aren&#x27;t rare. Leaks of high value private keys are very rare.<p>Offhand the only ones I remember are D-Link&#x27;s leak of a code signing key this year and AMI&#x27;s leak of a BIOS signing key a couple years ago. I&#x27;ve probably forgotten some.<p>Keys of this value are generally not stored online, and are often split using a secret sharing system among several people.<p>It&#x27;s not hard to set up a system where all of the decryption of the encrypted symmetrical keys of seized phones takes place on a computer that has no network connection and no interface to the outside world other than CD-RW discs [1].<p>Of course just because there are ways to manage the private key and its use in such system that are arbitrarily safe that doesn&#x27;t mean that the FBI would <i>actually</i> handle their key properly. If they do lose control of it, it would be bad.<p>My point, though, was just to illustrate that it is not the case that providing warrant access requires putting in a backdoor that completely opens up the system to anyone who knows about the backdoor and then hoping to keep knowledge of the backdoor hidden.<p>Also note I&#x27;m only trying to design this for data stored on phones and tablets, not for communication systems or servers.<p>[1] Thumb drives would be more convenient, but they contain electronics and interface via a port that is very hackable.