Re: Supply Chain Cryptographic Event Logs (was Re: [PROPOSED WORK ITEM] CEL DID Method (did:cel))

No changing the value, changing who has control.  We normally thing of did:cel as a way for a single person or org to manage things like key rotations or even (with did:webvh) transfer between domain hosts.  But the event log already has the idea of current key control being passed to next key control in a verifiable witnessed way.  Just instead of rotating keys for the same party, the proposal is to transfer key control across parties. 

Steve Capell
UN/CEFACT Vice-Chair
steve.capell@gmail.com
+61 410437854



> On 20 Jan 2026, at 2:43 pm, Michael Herman (Trusted Digital Web) <mwherman@parallelspace.net> wrote:
> 
> RE: the did:cel of the consignment which is the Credentialsubject of the BoL, not the issuer. Transferring control of the consignment did (not the carrier did) seems achievable with the event log.
> 
> This sounds like one is trying to use a VH to surgically change the value of the credentialsubject.id in an existing VC?
> 
> Is this possible Many?
> 
> Get Outlook for Android <https://aka.ms/AAb9ysg>
> From: steve capell <steve.capell@gmail.com>
> Sent: Tuesday, January 20, 2026 4:38:15 AM
> To: Michael Herman (Trusted Digital Web) <mwherman@parallelspace.net>
> Cc: Manu Sporny <msporny@digitalbazaar.com>; W3C Credentials CG <public-credentials@w3.org>
> Subject: Re: Supply Chain Cryptographic Event Logs (was Re: [PROPOSED WORK ITEM] CEL DID Method (did:cel))
>  
> Well, first acknowledging that this is a thought experiment and could be wrong, I think the answer may be to clearly separate two things: 
> 
> the did:cel of the carrier that issues the BoL VC - that cannot be transferred because of course it identifies the carrier not the consignment.
> the did:cel of the consignment which is the Credentialsubject of the BoL, not the issuer.  Transferring control of the consignment did (not the carrier did) seems achievable with the event log.
> 
> Regards,
> 
> Steve Capell
> UN/CEFACT Vice-Chair
> steve.capell@gmail.com
> +61 410437854
> 
> 
> 
>> On 20 Jan 2026, at 2:27 pm, Michael Herman (Trusted Digital Web) <mwherman@parallelspace.net> wrote:
>> 
>> RE: https://chatgpt.com/s/t_696ef188bd6c8191b902a5d0ebc44791
>> 
>> The next step (using option 3) is the really interesting one: how do you change the controller DID? ... presumably, the controller DID in the BOL VC... which the BOL VC itself isn't supposed to change. If/how can a VH solve this? I don't think it can?
>> Option 3: https://chatgpt.com/s/t_696ef4a830fc8191a7e767a86a4b6c51
>> 
>> Get Outlook for Android <https://aka.ms/AAb9ysg>
>> From: Steve Capell <steve.capell@gmail.com>
>> Sent: Tuesday, January 20, 2026 4:09:01 AM
>> To: Michael Herman (Trusted Digital Web) <mwherman@parallelspace.net>
>> Cc: Manu Sporny <msporny@digitalbazaar.com>; W3C Credentials CG <public-credentials@w3.org>
>> Subject: Re: Supply Chain Cryptographic Event Logs (was Re: [PROPOSED WORK ITEM] CEL DID Method (did:cel))
>>  
>> Here’s a ChatGPT conversation that highlights the issue https://chatgpt.com/s/t_696ef188bd6c8191b902a5d0ebc44791
>> 
>> This is the rationale behind international model law from un/citral on transferable records (Google MLETR) 
>> 
>> Steven Capell
>> UN/CEFACT Vice-Chair 
>> Mob: +61 410 437854
>> 
>>> On 20 Jan 2026, at 1:55 pm, Michael Herman (Trusted Digital Web) <mwherman@parallelspace.net> wrote:
>>> 
>>> 
>>> A BOL is a 2-party contract between a consignee and a shipper. It can be easily represented as a VC with a 2 x proof proof-set. Once the shipment is consigned, it doesn't change. 
>>> Reference: https://www.maersk.com/support/faqs/two-purposes-does-a-bill-of-lading-serve
>>> 
>>> If you want to track delivery status and/or delivery confirmation, those are different documents (different VCs, typically single party).
>>> 
>>> 
>>> 
>>> Get Outlook for Android <https://aka.ms/AAb9ysg>
>>> From: steve capell <steve.capell@gmail.com>
>>> Sent: Tuesday, January 20, 2026 12:14:19 AM
>>> To: Manu Sporny <msporny@digitalbazaar.com>
>>> Cc: W3C Credentials CG <public-credentials@w3.org>
>>> Subject: Re: Supply Chain Cryptographic Event Logs (was Re: [PROPOSED WORK ITEM] CEL DID Method (did:cel))
>>>  
>>> Hi Manu,
>>> 
>>> Thanks for this assessment.  We could be thinking the same thing.  
>>> 
>>> I didn’t mean that the did:cel would contain the entire bill of lading.  Assumed that would be a VC.  I assumed that the issuer of the VC is the original carrier.  The subject of the vc is the consignment identified by a did:cel.  And so the transfer of control is achieved by transferring the underlying did:cel consignment ID to a new controller (aka title owner).  So verification is “yes it’s a valid BoL and issued by a known and trusted ocean carrier, I see that the Consignment id is also represented as a did:cel, now who currently controls that did:cel because that are also the current title holder”.   Is that more or less what you were thinking or am I off track?
>>> 
>>> Steve Capell
>>> UN/CEFACT Vice-Chair
>>> steve.capell@gmail.com
>>> +61 410437854
>>> 
>>> 
>>> 
>>>> On 20 Jan 2026, at 9:42 am, Manu Sporny <msporny@digitalbazaar.com> wrote:
>>>> 
>>>> On Sat, Jan 17, 2026 at 9:05 PM steve capell <steve.capell@gmail.com> wrote:
>>>>> Transferrable records.
>>>> 
>>>> I'm not sure the core of that flow is a did:cel or a did:webvh use
>>>> case -- it could be a VC use case where the bill of lading has a
>>>> controller that is set at every step of the journey by the previous
>>>> controller... where the changes to each re-issued VC are wrapped up in
>>>> a Cryptographic Event Log (CEL). So, you could punt the NFT and
>>>> blockchain network to the curb and just depend on raw/dumb
>>>> HTTPS-accessible storage to "hold" the latest version of the bill of
>>>> lading.
>>>> 
>>>> Don't get me wrong, you could model the ocean bill of lading as a DID
>>>> Document, where transfer of ownership is done via key rotation or
>>>> something like that. That's one of the benefits of Linked Data -- you
>>>> can embed graphs of information just about anywhere. That is also one
>>>> of the drawbacks -- you have many ways that information can be
>>>> modelled and we depend on a body like UN/CEFACT to tell us all how to
>>>> do it.
>>>> 
>>>> So, this could look something like:
>>>> 
>>>> 1. Original bill of lading (BOL) is issued by the Shipper. BOL becomes
>>>> the first entry in cryptographic event log with Shipper as controller.
>>>> 2. Shipper transfers cargo to Carrier. Shipper sets Carrier as
>>>> controller and digitally signs VC. Updated BOL becomes second entry in
>>>> cryptographic event log with Carrier as controller.
>>>> 3. Shipper shares latest BOL in cryptographic event log with Bank,
>>>> bank releases payment to Shipper. Shipper sets Bank as controller and
>>>> digitally signs VC. Updated BOL becomes third entry in cryptographic
>>>> event log with Bank as controller.
>>>> 
>>>> I probably messed something up in the steps there (you are the expert
>>>> here, not I), but I hope you get the gist of how it might work with a
>>>> cryptographic event log. The DIDs would be the long-term identifiers
>>>> for the entities (Shipper, Carrier, Bank, etc.) -- those could be
>>>> did:web, did:webvh, did:cel, doesn't matter as long as they meet the
>>>> needs of the ecosystem. Digital signatures to "transfer ownership"
>>>> would be based on keys associated with each controller's DID.
>>>> 
>>>>> Long lived assets.
>>>> 
>>>> Yes, we are looking at CELs for this, and they'd mirror the sort of
>>>> thing going on with BOL above (except simpler -- usually just
>>>> buyer-seller transfers are recorded in the CEL over time).
>>>> 
>>>>> Authoritative issuers.
>>>> 
>>>> CELs may or may not play a role here -- you can combine DIDs with VCs
>>>> and CELs to get to multiple variations of what you're talking about
>>>> that work without the need for a blockchain (since you noted that
>>>> blockchain adoption is difficult in the supply chain space).
>>>> 
>>>>> Either way the market sees us as solving business problems through consensus rather than a bunch of techies arguing about who’s did method is better (no offence intended !).
>>>> 
>>>> Yes, agreed.
>>>> 
>>>> -- manu
>>>> 
>>>> -- 
>>>> Manu Sporny - https://www.linkedin.com/in/manusporny/
>>>> Founder/CEO - Digital Bazaar, Inc.
>>>> https://www.digitalbazaar.com/
>>> 
>