The creator of the homegroup generates
a 2048-bit RSA key pair, as
specified in [RFC3447] and [PKCS1].
These keys are encrypted, as described in section 220.127.116.11.5,
and sent to the other members of the homegroup over the PeerGroup
channel via a HomeGroup Signing Key message (section 18.104.22.168.5).
The keys are used to sign or verify the integrity of signed WSD
messages sent over the homegroup.