[Sat] Question about asset-identifiers

[Thomas Hardjono <[e-mail]>]

Folks,

Earlier this week I received a question about SATP-core, specifically about digital asset identifiers in the origin network (NW1) and in the destination network (NW2).

The digital asset identifier (DAI) is described very briefly in Section 5.2.3 of draft-core-03 as a UUID.

The question looks simple, but has some twists related to traceability of asset transfers (i.e. regulated assets and taxation) and privacy:

-- Assume the digital-asset is recorded in NW1 (i.e. in the ledger or database) as having an identifier DAI01.  After a successful transfer to NW2, the asset is assigned a new identifier DAI02 in NW2.

-- Question: should NW1 be aware of the new identifier DAI02 in NW2?   (for example, the new identifier DAI02 is reported back from gateway G2 to gateway G1 within the ACK-Final-Receipt message (message 3.7 of draft-core-03)).

-- The implication concerns privacy:  if the new identifier DAI02 is also copied (recorded as plaintext data) in NW1, this may permit other participants (other asset holders) in NW1 to know the new owner of the asset in NW2.


My response was that only the hash-of-DAI02 should be recorded in NW1.

So, the ACK-Final-Receipt message sent from gateway G2 to G1 should have the following parameters (where these will be recorded as data onto NW1 by G1):

Identifier of G1 and G2 (who handled the transfer instance).
The network identifier NW2 (to where the asset was transferred).
The asset identifier DAI01 (which is already known in NW1).
The hash of the asset identifier DAI02 (as it is known in NW2).
Date/timestamp.


As a corollary, when gateway G2 mints and assigns the new asset in NW2 (i.e. assign asset to Bob in NW2 immediately following the Commit-Final-Assertion message 3.5), gateway G2 should also record the hash of identifier DAI01 to NW2:

Identifier of G1 and G2 (who handled the transfer instance).
The network identifier NW1 (where the asset originated from).
The asset identifier DAI02 (the new identifier in NW2).
The hash of the asset identifier DAI01 (as it was known in NW1)
Date/timestamp.


Any thoughts?


--thomas