Apple released an [open letter][1] to the public outlining their reasons for not complying with the FBI's demands to modify the iPhone's security mechanism.

Here's a summary:

 - The FBI has an iPhone in their possession which they would like to access data from. The phone is locked and fully encrypted.
 - After failing to get into the phone, the FBI asked Apple to unlock the phone.
 - Apple said since the phone is encrypted, they can't get into it either.
 - The FBI asked Apple to modify the iPhone OS to enable brute force password attempts electronically. (Currently the passwords can only be entered in via the manual interface, and is limited to 10 attempts.)
 - Apple refused. They believe it would be too dangerous to make that change because in the wrong hands it would undermine the security of all iPhone users, even if they only used the software in this instance.

I understand Apple's position of not wanting to make the change, particularly for new phones, but it's unclear whether the change could actually be made and installed on an existing locked and encrypted phone. Could they actually accomplish this for an existing encrypted phone? If yes, then isn't simply knowing this is possible also undermining the security? It seems to me it would be just one step removed from the backdoor they are trying to keep closed.




  [1]: http://www.apple.com/customer-letter/