Same here.
I made this point in this thread:
https://forums.macrumors.com/threads/509617/
I said:
"I was wondering about losing my iPhone. And at some point I realised that I don't really mind so much buying a new one if I lose mine. More difficult is the fact that my iPhone contains my emails and address book, personal data comparable to what's on my computer rather than a traditional mobile phone."
"Why didn't Apple just encrypt everything???"
End said.
And here are some replies:
"anyway, can you not use, and change often, a 4 digit code?"
"Or you could just do a remote wipe if you lose it. A lot more convenient"
[Note: I don't know how to do that.]
"What difference would the encryption make? Presumably when you enter the code correctly the encryption would be bypassed and the data would be accessible or it'd be difficult to use the phone? In that case, your only real protection is the code (just like it is now) because if someone gets the code they get the data."
[Note: bypassing the code wouldn't allow access to encrypted data which needs the code for decrypting.]
"But your information is already protected by a 4-digit code (if you have that on). If you're actually worried about someone physically taking your iPhone apart, ripping out the flash chips and putting them into some sort of reader to access your data, I hope you've got your underground lair swept for bugs and all your phone lines monitored for wiretaps. Oh, and watch out for the CIA assassins."
[Note: Actually, I do have my underground lair swept for bugs.]
End replies.
And here's the solution I proposed:
1. Encrypt the data with a 10-letter password.
2. Whenever the phone is switched on (from power-off), ask for the 10-letter password.
3. Store the password in memory while the phone is on (or sleeping) and use it to decrypt the data on the fly when the phone is in use.
4. If the phone is switched off (to power-off), lose the password from memory (naturally). If the phone hasn't been used for a (configurable) number of hours, lose the password from memory.