key-signing key flag [1] & wildcard-optimization [2]

1Olaf M. Kolkman . IETF55, November 2002, Atlanta GA . http://www.ripe.net/disi/

key-signing key flag [1]

&wildcard-optimization [2]

Olaf Kolkman[1] with Jakob Schlyter

[2] with Johan Ihren and Roy Arends

Olaf M. Kolkman . IETF55, November 2002, Atlanta GA . http://www.ripe.net/disi/ 2

Key Signing Key (KSK) Flag

draft-ietf-dnsext-keyrr-key-signing-flag-03

with Jakob Schlyter


The Gist

• Operational need to distinguish between key-singing keys and zone-signing keys.

• Not used in the protocol and verification process but useful for troubleshooting and key exchanges.

• Use the 15th bit so that the parity determines the ‘role’ of the key, that’s for us… humans.


Example

Before:net 300 IN KEY 256 3 5 Ox1tVxw+j...

300 IN KEY 256 3 5 OTxq2ce5J...

After:

net 300 IN KEY 256 3 5 Ox1tVxw+j...

300 IN KEY 257 3 5 OTxq2ce5J...

KSK


What’s next

• Final update and last call?


DNSSEC Wildcard Optimization

draft-olaf-dnsext-dnssec-wildcard-optimization-01

with Johan Ihren and Roy Arends


Background

– Assumption: One needs proof for non-existence of a wildcards.

– The proof is to be supplied in the common case where there is no wildcard in a zone.

– That proof is complicated and somewhat expensive in terms of computational resources and packet size.

– Is there a way to signal that there is no wildcard in a zone?


Very common case

• Root will need to proof that *. does not exist.

• As an aside:– Some people love the idea of a wildcard

at the root


The proposal

• Use a bit in the NXT RRs type bitmap to signal non-existence of wildcards

• The meaning: There is no wildcard expansion possible of any name in the zone’s namespace spanned by a NXT RR.

• Simplest algorithm to set the bit:– Turn it on on all NXT RRs in the zone if there are no

wildcards in the zone– Turn it of on all NXT RRs in the zone if there is any

wildcard in the zone


Server side

• If the NXT RR proving the non-existence of an exact match has the bit set then no further NXT RRs are needed.

• If the bit is not set on that NXT RR a full denial of existence needs to be served.


Resolvers Side

• When bit is set on the NXT RR proving the denial of existence of the QNAME, no further proof is needed;

• Full RFC2535 type proof of non existence is to be expected and processed if the bit is not set.


Pros and ConsPro:• Shortcut to a simple and fast code path for server

and resolver in the case there are no wildcards.• Smaller footprint on the wire and in caches.

Con:• Although bypassed in the ‘common case; the

complicated verification code is still needed. • Special meaning of type bitmap bit:

– RR type code without RR.– Backwards incompatible (needs to piggyback on DS flag

date)


Current version of doc.

• The suggested algorithm for setting the bit contains an error – Details will be posted to namedroppers

• Clarifications are needed


What’s next

• Update the draft

• Does the working group think this is a sane path.

General comment:• DNSSEC protocol specs need to describe

algorithm for denial of authentication of wildcards– If not, resolver implementers will do it wrong.– No need for more than 2 NXT RRs? (Give me an

example that needs more.)


Questions???

• http://www.ripe.net/disi• [email protected]

key-signing key flag [1] & wildcard-optimization [2]

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