Centralized ways of proving identity may soon have an expiration date.

A lofty claim, perhaps, but the idea is arguably bolstered by the launch this week of a functioning blockchain prototype this week built by Microsoft and Accenture. The technology could one day allow users to accumulate verified information about their identity in a profile they control.

Instead of permanently handing over that information to a university, a healthcare provider or a potential employer, the owner of the identity could choose exactly who gets access to what data – and for how long.

The global head of Accenture's capital markets blockchain practice, David Treat, explained in the first live demo of the prototype how any number of identity sources can be aggregated under a single profile.

Speaking on stage at the ID2020 conference hosted earlier this week, Treat explained:

Powered by a private version of the ethereum blockchain, the prototype runs on Microsoft's Azure cloud computing platform, according to an Accenture statement, and sets out to comply with principles established by the Decentralized Identity Foundation, co-founded by Microsoft.

Instead of reinventing how identity itself is proved, the prototype, developed with assistance from managed service provider Avanade, acts as a cryptographically protected store of data verified by existing identity providers.

While the owner of the identity has ultimate control over the access, once permission is granted to a third party it can be queried for authenticity, and if any part of the information is in doubt, the recipient can "pull on that thread", as Treat put it, and go back to the original source.

Yet, when the allotted time expires, any access to the identifying data is permanently revoked, meaning profiles do not "accumulate" over time.

The distributed ledger is designed to be maintained by participating parties, while simultaneously preventing personally identifiable information from being viewed by those parties.

Though the demo was conducted using a smartphone user interface, Treat said any number of formats could eventually be employed.

Should the prototype be released to the public, the network of users will likely employ Accenture's Biometric Identity Management System to gain initial access, according to a company statement. The service has already been used in the field by the United Nations High Commissioner for Refugees (UNHCR) to enroll 1.3 million refugees in 29 countries.

"The platform we used allows for the capture of any form of biometric identity, whether that’s voice, or face, or whatever," Treat said.

All in all, the ethereum-based app was built over a six-week period earlier this year in Dublin, Ireland. Created by a team at The Dock, a new research and incubation hub establish by Accenture, the app is still in the early stage of development.

However, Treat emphasized that it does in fact work as intended and shouldn't require years to deploy, as is frequently the time-frame proposed for blockchain projects at this early stage of the technology’s development.

In remarks after the demo, Saadia Madsbjerg, managing director of the Rockefeller Foundation (which helped fund the project), said the group was aiming to have a finalized technical proof-of-concept and multiple pilot projects up and running as soon as 2020.

By that time, Accenture’s Biometric Identity Management System is expected to have increased the number of identities it hosts to 7 million refugees from 75 countries, according to the statement.

Following Madsbjerg’s remarks, Treat concluded:

App demo image via Michael del Castillo for CoinDesk