security of bluetooth keyboard during boot / mounting root cryptfs

[scar]

i have a system running 10.04 which has the / (root) partition encrypted
and so i am asked for the passphrase when ubuntu boots up.  but the
system is also using a bluetooth keyboard/mouse and i am wondering if
the communication between the keyboard and the receiver is secure during
this part of booting?  it seems after i enter the passphrase and before
i am able to log on, the bluetooth connection is reset while the
bluetooth service starts and re-pairs the keyboard.  does the system use
some sort of insecure connection during bootup before the bluetooth
service is started?  thanks