I knew that.
Yes, the data on iCloud is encrypted with the same Key.
I did not know that, thanks for the info.
But since the owner is dead, and only he knows the passcode, there is no way to re-create the key.
Right, or more specifically no way to extract it from the HW where it is stored.
Actually the key is not stored in the Hardware. That's one of the reasons the iPhone IS so secure. What is stored on the hardware is a one-way HASH code that represents the passcode.
When the user inputs his passcode, a hidden (hard coded in silicon on later model iPhones) algorithm re-creates that one-way HASH and the new HASH is compared to the one stored on the device. If they are the same, the device is unlocked and start-up continues. The passcode is then passed on to another algorithm and is entangled with the hidden UUID and Group ID along with some hidden data that were collected when the iphone was first started to create the encryption KEY. This is then AGAIN compared to a one-way HASH stored in the Secure Element (on later devices) and if validated, the data the users needs for that session of using the iPhone will be deciphered as needed on the fly, and encrypted as needed when stored. When the iPhone is closed, everything saved is re-encrypted. Then the volatile memory is erased to assure safety of data until the next time the user logs in.
Once the comparisons are made, the passcode is erased and not kept on the device so no current attempt to read it can find it. At no time is the user's passcode ever kept on the device.