Wild Speculation on iPhone 3G S Hardware Encryption

I'm pretty sure they encrypt the entire flash with a random key that is stored in the first page. When remote wipe request comes in you just need to nuke the key to destroy data, which is a lot faster than actually overwriting 32Gb of flash.<p>iTunes backups are not encrypted by default because you have a key management issue. The primary purpose of the backup is so that you can restore it to a different device after your main device is lost or broken. Since devices where backup is taken and restored are different you can not use built-in key to encrypt the data. There are only two options where to store the key - with the backup itself (which is entirely useless) or with the user. Which is exactly what iTunes does - it allows the user to specify a password that is used to generate the key.

Wild speculation makes the front page? They probably put in a hardware block encryptor, which is generally useful for encryption (look up Secure Virtual Memory in Mac OS X). Yes, it is faster to wipe a block key than to wipe an entire flash drive, but this post should have ended there instead of speculating that Apple's engineers don't understand encryption.<p>If you like wild speculation, it is likely that the block key is large enough to provide adequate security, and that it is stored locally but encrypted with a data encryption method like RSA. The password for this might be as simple as a 4 digit pin, but thats irrelevant because the encrypted encryption key would be the first data wiped in the event of a data breech. If you're really paranoid, you could store a larger key on the network. Rebooting the device would then require network access, but it protects you against someone removing your compact flash and reading it directly.<p>Obviously backup files are not encrypted, or they wouldn't be very useful. If they are encrypted, it will only be as strong as the user specified password, or key stored on MobileMe.