None. You'll simply have to trust that we have configured your TKey with a UDS of good entropy, and that we haven't saved it - intentionally or unintentionally.

None. You'll simply have to trust that we have configured your TKey with a UDS of good entropy, and that we haven't saved it - intentionally or unintentionally. However, the device's flexibility allows you considerable control. For instance you could have its KDF mix in a user-supplied secret in addition to the UDS. Of course you'd still be trusting that the device actually performs the KDF we claim it does. That's why we also sell the TKey Unlocked.