Hi Luveh,

when just re-signing the zone, Knot does not need to generate any newer key pairs. It's just still using the key pair it has generated initally (for each zone separately).

Only in the case of ZSK and KSK rollovers, when the keys (ZSK and KSK, respectively) reach their configured lifetime, new keys are generated and old are rolled-over (in a bit complicated, multi-step process) and deleted afterwards, so that in usual case, only 2 keys per zone are present.

In case of single-type signing scheme, it's just one key per zone (CSK).

Anyway, any keys can be deleted (if needed) by the keymgr utility. One just needs to check that the key being deleted is not needed anymore ;)

Libor

When Knot generates a key pair, it will save it in some directory in the filesystem - in the clear, when using the default cryptographic provider, or as an encrypted blob when using SoftHSM, or (possibly) a real HSM.

Imagine that I have a setup with many zones, with a signing policy that causes them to be re-signed often - say, every hour or so. This implies that new key pairs will be generated all the time. 

My question is, how does Knot manage key pairs that it does not need any more? It does not seem to remove them automatically. Does it provide any mechanisms or tools to do so?