It sounds a lot better than trying to remember 20 different passwords, and more secure than giving up and using the same password for every site.
Sovrin says its online ID could be used to lower costs and address security concerns in areas like banking, address privacy issues in healthcare and help prevent electronic voter fraud and other types of online identity theft.
There are already various local attempts to create a single, secure online identity, including Internal Affairs' RealMe in New Zealand.
However, RealMe illustrates that problems creating a single online ID system are more commercial and political than technical.
It's been hard yakka for the homegrown effort, with still lots of noteable holdouts five years after RealMe's launch, including ASB, BNZ, Trade Me and large parts of the health system - though it is starting to gain traction.
Sovrin, by contrast, is a global effort.
It had developed a respectable list of members (or "stewards" in Sovrin-speak) since it was founded in 2016, including US tech giants Cisco and IBM.
But there's a way to go yet. To go mainstream, it will need thousands of members, not dozens.
A rep for Spark says, "We're not disclosing financial commitment but it is relatively small."
And the company is still talking in relatively woolly terms about what its Sovrin membership could mean in terms of future Spark products.
"In regards to our role as founding steward, this is really about contributing to a framework rather than any particular commercial proposition," the Spark spokeswoman says.
"Although there will likely be commercial opportunities arising from the framework down the track."
Unlike bitcoin, blockchain's distributed technology is well-regarded by analysts as a transparent, secure and low-cost way of doing business. Most see the technology going mainstream, once everyone's on the same page and up to speed.
Notably, Spark avoids using the term "blockchain" at all in its Sovrin announcement, despite Sovrin itself using it 56 times in its own description of its framework.
The telco users "distributed ledger" instead, perhaps to avoid the bandwagon-jumping connotations of blockchain, or the negative association with the tanking bitcoin.
Spark says its Sovrin commitment is the first initiative arising from last week's announcement that the is forming a new subsidiary business entity, led by Dr Claire Barber, to focus on long-term, large-scale new business opportunities arising from a range of emerging technologies.
Barber was last seen leading the telco's "agile" restructure.