[sidr] question on SKI and router public key retrieval in signature attribute in BGPSEC

[nalini iyer <[e-mail]>]

Sorry for asking this but despite looking at likely sources  off the
documents list on the SIDR page am still in the dark, and would like
to confirm suspicions.

The SKI in the signature attribute is a hash of the signing router's public key,

a) Is this hashed with the CA's pvt key?
b) How is the corresponding CA certificate (to de-hash the SKI) obtained?
c) From where is the router EE cert identified by the SKI then
obtained, or is getting the router's cert considered  unnecessary as
the router  public key is contained in the de-hashed SKI?
thank you,
N.I.