[mehrdada]

I am no expert in that sort of stuff, so I have no estimate of the difficulty of it. I'd imagine it's too costly to be worth doing on every random iPhone in every random investigation, but if someone really really wants it, then yes. The weakest link most of the time remains the stupid unencrypted iCloud backup.

If you actually care about security, use a long alphanumeric password. It's not a big hassle when you have Touch ID. If you are ever in trouble, try turning the iPhone off immediately or quickly touch your fingerprint reader a few times with a wrong finger or enter the passcode wrong five times (so that Secure Enclave discards the cached decryption key and no longer accepts fingerprints). Also, use Apple Configurator tool to make your iPhone "Supervised" and don't let it pair with any new computer. And disable iCloud backup entirely.

[beeboop]

If you really care about security from an organization like the NSA, the only option is either to have it be entirely air gapped or to be entirely open source, including BIOS and UEFI firmware and anything else that might run on the hardware. There are really no feasible options, and especially so in phones.

[rimantas]

It's amusing to see open source still promoted as panacea after all those OpenSSL exploits.

[ionised]

It's obviously not a panacaea, but it does have the quality of allowing audits by the community and by independent experts in the field.