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Your point about a TPM PIN being more secure than a password doesn't make sense. Both are passwords. If you're assuming the user stored their PIN safely, then y
by samrus 3y ago
Your point about a TPM PIN being more secure than a password doesn't make sense. Both are passwords. If you're assuming the user stored their PIN safely, then you can also assume they would store their password safely.
Your broader point is fair though. Because this explout is nullified by a built-in TPM (already here) or the lanes being end to end encrypted (ship has sailed)
- lozenge 3y agoI think they mean a Windows password. You enter it after the disk is already decrypted.
- dist-epoch 3y agoSecurity in depth. TPM+PIN prevents taking/imaging the drive and trying an offline attack. And TPM is rate-limited, another security in depth feature.
- jeroenhd 3y agoOne is a password, the other is an unlock phrase for a securely generated key. Password based keys need to go through PKDFs and have limited entropy. A "PIN" in the TPM sense is alphanumeric and will be entered the same way the user enters a passphrase, except the secret that actually protects the disk isn't derived from that passphrase. It's much harder to brute force a TPM PIN than it is to brute force your average PKDF function. The brute force complexity grows to encompass the full key space rather than the key space of a key derived from memorable alphanumeric text. With a proper passphrase this probably won't matter much in terms of feasibility, but a lot of users pick terrible passwords that are easy to brute force with a whole bunch of servers, while with a TPM chip an attacker would need to choose another method (i.e. attacking the TPM itself).