Colliding with what? Just the other keys it is writing at the time? > Or do they need to see all active keys? Or all keys they have ever > created for this zone? Or...
Looking at it from a validator perspective, collisions can affect validation in two major ways: 1) There are two (or more) keys in a DNSSEC RRset that match a DS record in the parent zone. This one is realively cheap, just a hash calculation. 2) There are two (or more) keys in a DNSSEC RRset that match an RRSIG record. This is the expensive part. So in short a DNSSEC RRset must not contain keys that have the same key tag (and the same algorithm). There are some exceptional condations that need to be taken into account. In a double signature ZSK roll, it is possible that the old and the new ZSK have the same key tag but never appear in the same DNSKEY RRset. So it would be good to prohibit a collision in this case as well. Ultimately, what validators need is a low limit on the number of signature validations that are allowed to fail. Collisions are obviously an issue, but there might be other parts of the protocol or operational pratices the cause problems. > It is easy for this group to come up with more MUST NOTs about > things we forgot in the past, knowing that they will not be > implemented. It is harder (but maybe better) for us to simply > describe the situation and how we got here. We have collisions. We got there because it takes effort to avoid them and there is no requirement to avoid them. How does this description help validators? _______________________________________________ DNSOP mailing list -- [email protected] To unsubscribe send an email to [email protected]
