Yes but the criticism I have of Sam's Keri doc is that it overloads the word centralised. Traditionally centralised has been contrasted with distributed, and refers to the location of the application/database etc. on the computers. But Sam then uses centralised to refer to control, and so contrasts centralised with decentralised. This leads to confusion, and to why some people still use distributed instead of decentralised when referring to SSI.

In CS it is never a good idea to use a single variable to refer to two different parameters. So we should not do this with the word centralised either.

I suggest we should continue to have centralised vs distributed as in the traditional use for a system's location.

And a new word such as Administrative to contrast with Decentralised for control i.e. Administrative control vs Decentralised control.

Kind regards


On 23/03/2021 19:10, Jeremy Townson wrote:
Everybody could benefit here by consulting Sam Smith's talk introducing KERI (given to the SSI meetup). He starts the process of redefining often overloaded terms more objectively -- 'infrastructure independence' for instance.

On Tue, 23 Mar 2021 at 18:47, David Chadwick <> wrote:

Hi Drummond

your characterisation is interesting but is not either a full or correct picture.

Firstly centralised could give a false impression of a single system, whereas all your centralised systems are distributed systems

Secondly Federated systems build on the former and cannot work without them.

Thirdly Verifiable Credentials are not inherently decentralised. They are no more decentralised than X.509 Attribute Certificates. Remember that VC IDs are defined as URIs in the standard, not DIDs. And X.509 ACs can bind attributes to keys in the same way as VCs do.

Fourthly, I have heard several academics describe blockchains as centralised systems, surprising as you may find this.

Fifth, self signed X.509 PKCs are just as decentralised as DIDs.

Kind regards


On 23/03/2021 16:57, Drummond Reed wrote:
Michael, the definition is in the first sentence of Chapter 1:

Self-sovereign identity—commonly abbreviated SSI—is a new model for digital identity on the internet: i.e., how we prove who we are to the websites, services, and apps with which we need to establish trusted relationships to access or protect pri- vate information.

That broad definition was a deliberate choice on behalf of Alex Preukschat and I as co-authors of the book. SSI is a digital identity model (not just an architectural model, but also a governance model) that is significantly different than in the digital identity models of the previous two eras of Internet trust infrastructure, per this diagram that I now show at the start of all my talks on SSI and ToIP to establish the overall context.


On Tue, Mar 23, 2021 at 9:27 AM Michael Herman (Trusted Digital Web) <> wrote:

Hi Drummond, I’ve read through Chapter 1 of the Manning book just now ( and couldn’t a succinct nor operational definition for the term/concept of Self-Sovereign Identity.


The chapter talks “all around” the topic of Self-Sovereign Identity but didn’t seem to conclude with an actual definition.  Did I miss it?


Michael Herman

Far Left Self-Sovereignist


From: Drummond Reed <>
Sent: March 23, 2021 10:02 AM
To: sankarshan <>
Cc: W3C Credentials CG (Public List) <>
Subject: Re: The "self-sovereign" problem (was: The SSI protocols challenge)


+1 to Adrian Doerk's definition in his thesis (which I highly recommend, BTW—Adrian's work is very comprehensive and thorough).


FWIW, even though the forthcoming Manning book of which I'm a co-author (along with 54 contributing authors) is titled "Self-Sovereign Identity: Decentralized Digital Identity and Verifiable Credentials", in the opening chapter we explain the origin of the term and then recommend (and enforce throughout the rest of the book) simply calling it "SSI"—which is also what I see happening in the market. I predict that within the next 2-3 years, many who have become comfortable with the term "SSI" won't even know that it is an acronym or what it stands for (just as many today don't know what "IBM" or "ATM" stand for). 


As a final point, I was a speaker this morning on a webinar hosted by Condatis called "Scaling Digital Trust in Healthcare" where Charlie Walton, VP Digital Identity at Mastercard, shared the following slide, which is the first time I've seen the term "Commercial SSI".






On Tue, Mar 23, 2021 at 6:54 AM sankarshan <> wrote:

On Tue, 23 Mar 2021 at 18:40, Michael Herman (Trusted Digital Web) <> wrote:

RE: "Decentralized identity" is a *better* choice. Others use "self-asserted," I think this has some of the same socio-cultural issues that "Self-sovereign" has.


  1. QUESTION: Why is there this pervasive (pandemic?) of thinking spreading across so many of our communities (CCG, SF, ToIP, etc.) about giving in to this type of authoritarian, centralizationist thinking? 
    Why are people giving up on self-sovereignty in such large numbers?

The representation such as the above often create an all-or-nothing inference on the topic of SSI. It feels appropriate to cite a recently published work Doerk, Adrian. (2020). The growth factors of self-sovereign identity solutions in Europe. 10.6084/m9.figshare.14182586. and especially


We use the terminology of self-sovereign identity for describing a concept of giving individuals or organizations control over their digital identity. The identity resides with the identity subject in question, who is central to its administration. Sovereignty implies that individuals are equal among peers and are not administered by a central authority. This doesn't mean that individuals can suddenly issue themselves a new passport. Instead it means that individuals have control over how their personal data is shared and used. Moreover, individuals can now choose whether they would like to reveal their personal data and also which kind of data they would like to share in the event of a transaction or interaction. Through the use of cryptographic proofs SSI enables verifiability for all involved parties.