Re: Information about HCI LE Rand command

Hi Alexandre,

Den mån 25 mars 2019 kl 13:03 skrev Alexandre Augusto
[off-list ref]:

Hello,

I would like to know, if possible, information about the bluez LE Rand
command (ocf 0x0018) at HCI code. How does it generate the number? Is
it vendor-specific (or secret)?

According to the Bluetooth core specification, it shall be a "A pseudo
random number generator compliant with [FIPS PUB 140-2]
(http://csrc.nist.gov/publications/fips/fips140-2/fips1402annexc.pdf)"
which shall be seeded "with at least the minimum entropy required by
the pseudo random number generator". What algorithm each Bluetooth
controller actually uses is therefore vendor specific. I guess most
controllers will use some SHA-based or AES-based algorithm. Note that
it is not the host (BlueZ) that generates the number; it just asks the
controller to generate it for the host.

/Emil