Minutes

Date of meeting: 30 January 2024

Item 1: Welcome

Tom Mutton (Chair) welcomed Members to the ninth meeting of the CBDC Technology Forum.

The Chair informed Members that a summary of responses to the Consultation Paper and a summary of responses to the Technology Working Paper were published on January 25, 2024.

The Chair noted that the agenda for the meeting would comprise presentations from two of the four subgroups that have been temporarily established to help explore the design options for the digital pound architecture. The Chair then invited members of Subgroups 1 and 4 to present the progress of their work to date.

Item 2: Subgroup 1 presentation

Members of Subgroup 1, tasked with exploring technology options to ensure privacy in a digital pound and the design of the alias service, presented on Subgroup 1’s approach and findings to date.

They stated that Subgroup 1’s goals were to define the data access requirements for payments and to assess different solutions against those requirements. They noted that Subgroup 1’s primary consideration was privacy, but there were other considerations that need to be adhered to, particularly as compliance with legal and regulatory requirements. They explained that those considerations could introduce challenges for achieving their requirements for privacy.

They also discussed Subgroup 1’s draft privacy model, which considered different types of data, including account data, personal data and transaction data. It also considered different roles, such as payer, payee, Payment Interface Providers (PIPs), the ledger operator and the alias service operator. They explained that complexities would arise if the ledger operator was also the alias service operator, and it would be important to explore how PIPs would communicate with each other, whether that is directly or through the ledger operator.

They explained that there were cryptographic techniques, such as zero-knowledge proofs, that could support privacy. However, work would be needed to determine the implications of those techniques for a digital pound system. They noted that there were other considerations that might impact their assessment of different technical solutions, including whether holding limits would be implemented.

Item 3: Subgroup 4 presentation

Members of Subgroup 4, tasked with exploring the requirements for providing a platform for innovation, presented their initial findings. They explained that they would propose nine experiments for the Bank of England (the Bank) to consider commissioning:

• The first experiment would take examples from smart contract platforms and implement them against the API-based platform model of the digital pound to determine technical and legal feasibility.
• The second experiment would involve the Bank creating a hub or sandbox that would enable technical stakeholders to develop innovative solutions and experiments using synthetic data.
• The third experiment would explore technologies that could protect the privacy of user balances.
• The fourth experiment would involve working with existing participants in the blockchain or distributed ledger technology space to explore potential use cases, such as a bridge component between the digital pound and Ethereum.
• The fifth experiment would explore seamless omnichannel refunds, which would allow consumers to request refunds directly from their wallet applications.
• The sixth experiment would explore how a digital pound could be implemented on a public chain.
• The seventh experiment would explore an innovation platform that would sit above the core digital pound system and support innovation across all forms of money.
• The eighth experiment would explore a common platform that would sit above the core digital pound system and support interoperability across all forms of money.
• The ninth experiment would use electronic signatures to enable authorisation for tap-and-go transit payments.

Item 4: Closing remarks

The Chair closed the meeting and thanked Members for contributions.

Attendees

Bank of England

Tom Mutton (Chair)

Danny Russell

Will Lovell

Members

Adrian Field, OneID

Alain Martin, Thales

Andrew Flatt, Archax

Ashley Lannquist, IMF

David MacKeith, AWS

Dominic Black, Ledgerz

Edwin Aoki, Paypal

Gary King, Lloyds

Georgios Samakovitis, University of Greenwich

Inga Mullins, Fluency

Joshua Jeeson Daniel, JP Morgan

Julia Demidova, FIS

Keith Bear, Cambridge Centre for Alternative Finance

Kene Ezeji-Okoye, Millicent Labs

Lars Hupel, Giesecke+Devrient

Lauren Del Giudice, Idemia

Lee Braine, Barclays

Mark Shaw, Spotify

Michael Adams, Quali-Sign

Paul Carey, Stripe

Richard Brown, R3

Sarah Meiklejohn, IC3

Simon Brayshaw, Motorway

Vikram Kimyani, Oracle

Will Drewry, Google

Observers

HM Treasury

Apologies

Alan Ainsworth, Open Banking

Bejoy Das Gupta, eCurrency

Geoff Goodell, UCL

James Whittle, Pay.UK

Paul Lucas, IBM

Tim Moncrieff, Visa

Tom Beresford, Starling