Question about encryption key derivation speed and the secure element

Virulent

I'm trying to decide how long my pin should be. I understand that, assuming the secure element is working as intended, a 6 digit pin will take over a thousand years to crack on average assuming a random pin. But what if the secure element isn't working as intended? For example, what if a malicious actor discovers a way to trick the secure element into thinking there have only been 0-4 failed attempts. According to the FAQ, this means there 0 delay, however, it says invalid input outside the minimum or maximum length limit of the UI won't work. What is the minimum length limit of the UI? Is that limit implemented in the secure element so even if an actor tricks the element into thinking there are less failed attempts than there are, there is still a small delay?

ryrona

Virulent I understand that, assuming the secure element is working as intended, a 6 digit pin will take over a thousand years to crack on average assuming a random pin.

This is not true. An exploit that totally undermine the security the secure element provides will be found way before then. I would not expect the secure element to be able to throttle login attempts at all anymore after 5-10 years from phone original release date.

So if you worry about your phone being taken, and need to be sure they cannot ever access your data during your life time or even within the next 10 years, follow @treequell advice and use a 6-8 word diceware password. That way, you are no longer dependent on the secure element at all for security.

Virulent

The reason I ask is because even if this minimum delay means, for example, 1 pin attempt per second, then a 6 digit pin is no longer secure but a 10 digit pin will still take 1-2 lifetimes to guess. Knowing this minimum delay would be useful in case the secure element is partially compromised such that the delay does not increase with failed attempts

treequell

Similar questions have been addressed before. It's recommended to use a strong passphrase such as 6-8 diceware words for a user profile with data you need secured forever regardless of exploits.

For more details see https://discuss.grapheneos.org/d/12848-claims-made-by-forensics-companies-their-capabilities-and-how-grapheneos-fares