Subject: [Tm-rid] IETF trustworthy IDs alternatives for tm-rid

From: Robert Moskowitz <[email-masked]>
Date: Thu, 17 Oct 2019 09:21:55 -0400

Eric challenged me to show why HIP/HITs for UAS RemoteID, and not 
something else in the IETF toolbox, so here goes:

Just a couple of requirements:

1)    The ID MUST be 20 bytes or smaller.

2)    It MUST be non-spoofable within the context of RemoteID broadcast 
messages (some collection of messages provides proof of UA ownership of ID).

3)    In context (that is in a RemoteID broadcast message), just the ID 
provides enough information on how at least the observer's USS (UAS 
Service Supplier) can provide both public and private information on the 
UAS.

Now a little 'context' setting.  ASTM has already defined a set of 
textual RemoteIDs:

1: Serial Number (ANSI/CTA-2063)
2: CAA Assigned ID
3: UTM Assigned ID (UUID RFC4122)

The work here MUST surpass these in terms of Trustworthy.

The options I have found in my research over the past couple weeks (and 
please add your knowledge to the list):

1)    X.509 certs where something like the cert sequenceNumber is the 
RemoteID
2)    RFC 6920 (Naming Things with Hashes), sec 8.2
3)    SSH keyID
4)    HIT (Host Identity Tag)

Option 1 is no better than what ASTM/FAA is considering for any of the 
current proposed types.  Somehow, there will be a PKI and from that 
knowledge of the UAS is gained.  This REQUIRES Internet Access (think 
disaster or other non-Internet situations) and a GLOBAL PKI (the UA flew 
from Canada to the US or UK to France post Brexit).

Option 2 meets requirements 1 & 2, but needs to be augmented so that the 
Hash provides context for 3.  Is it supported for IPsec and/or QUIC for 
UAS/observer secure communications (phase 2).

Option 3 is similar to 2, but has a significant collision issue for 
global use.

Option 4 is similar to 2, but needs significantly less augmentation.

If I look at the work to make any of these a real value-add to US 
Remote/NetworkID, my money is on HIT/HIP as the most complete.

More details to follow in the ID that Stu and I are supposedly writing 
and for the BOF.

Bob