Minutes of the CBDC Technology Forum – September 2021

Minutes

Item 1: Objectives and proposed format of Technology Forum meetings

Tom Mutton (Chair) welcomed the Members and attendees to the first CBDC Technology Forum meeting. He
explained the objectives of the Forum. The Technology Forum would not have any decision-making
responsibilities nor any formal advisory or consultative function. However, it would have an
important role in helping the Bank to understand the views of expert stakeholders on the
technological challenges of designing, implementing and operating a CBDC. To this end, the Bank
encouraged Members to suggest topics for future agendas and to lead certain discussions – this would
be explained further under Item 3.

The Chair reminded Members of their roles and responsibilities on the Forum. Members were expected to
act in a personal capacity and to share perspectives that reflected their constituency as a whole,
rather than representing the interests of their individual organisations. The Chair noted that the
Technology Forum was being held under the Chatham House Rule, and the minutes would be published. To
encourage the frank exchange of perspectives, Members should refrain from revealing publicly any
information about meetings that was not included in the published meeting minutes.

Item 2: Recap of some assumptions around CBDC technology

The Bank set out its current views around the potential technology choices it faced in designing and
delivering a CBDC^{footnote [1]}. Whilst it was important to
clearly determine requirements before deciding on CBDC technology choices, the Bank was already
researching, in some depth, technology options to see what approaches might be relevant and
feasible. Recapping on design characteristics, the Bank explained a CBDC system should be reliable
and resilient, fast and efficient, innovative, and open to competition. And as a general principle,
the core ledger infrastructure for CBDC should be kept as simple as possible, with more complex
functions provided by overlay services.

The Bank reminded Members of the ‘Platform Model’ for providing CBDC as set out in the 2020
Discussion Paper^{footnote [2]}, but other models for CBDC were
also under consideration. Some Members suggested that an alternative model for CBDC provision would
be a ledger-less, digital bearer instrument – essentially a cash-like CBDC. This model might be
beneficial for privacy and capacity for offline payments. However, other Members queried the
feasibility of this approach, both in terms of the viability of the technology, and in relation to
resilience, and prevention of tampering and “double spending” of CBDC units. The topic of offline
payments and “double spend” risk would be considered for further discussion at a future meeting.

Items 3 and 4: Forward agenda and Members’ views on key CBDC technology topics

The Bank set out a potential forward agenda of topics for the Technology Forum. The Bank indicated
that future meetings would include Member-led presentations with the aim of two presenters from
different organisations introducing each topic, to ensure a variety of points of view.

Members had a variety of suggestions for topics that might be discussed in future meetings. Members
emphasised the importance of addressing interoperability of CBDC with other payment rails, as well
as interoperability between Payment Interface Providers in a CBDC system; and considered they should
be priority topics for discussion. Members also indicated significant interest in discussing offline
payments, privacy and programmability. Further suggestions included the role of and technology
dependencies on Payment Interface Providers in a CBDC system; the importance of user experience,
accessibility and CBDC interface design; and processes for changes and upgrades to CBDC technology
design were one to be launched. One member asked whether a UK CBDC had been defined to be purely
retail versus also encompassing ‘wholesale’ transactions (e.g. between financial institutions). The
Bank noted that whilst many of the discussions were focussed on a “retail-focused” CBDC, given its
novelty and the technology challenges it might present; technology considerations for wholesale CBDC
was also very much within the scope of topics open for discussion.

Members also discussed the structure and sequencing of when topics might be explored at the Forum,
and the challenge of ensuring focussed conversations given the cross-cutting nature of many topics.

Closing remarks

The Chair closed the meeting and thanked the Members for their contributions. Subsequent meetings
would be slightly longer in duration and the Bank would look at hosting hybrid in person/ virtual
meetings so Members had the option to attend at the Bank.

Annex: Meeting documents

Attendees

Tom Mutton (Chair), Bank of England

Simon Scorer, Bank of England

Will Lovell, Bank of England

Rachel Greener, Bank of England

Katie Fortune, Bank of England

Ben Dovey, Bank of England

Zerina Joseph, Bank of England

Members

Alan Ainsworth, Open Banking Implementation Entity

Andrew Flatt, Archax

Ashley Lannquist, WEF

Bejoy Das Gupta, eCurrency

David MacKeith, AWS

Dominic Black, Monzo

Edwin Aoki, PayPal

Geoff Goodell, UCL

Inga Mullins, Fluency

James Whittle, PayUK

Joshua Jeeson Daniel, SETL

Keith Bear, Cambridge Centre for Alternative Finance

Lauren Del Giudice, Idemia

Lee Braine, Barclays

Mark Shaw, Spotify

Matthieu Saint Olive, Consensys

Max Malcolm, Visa

Michael Adams, Quali-Sign

Patrick O’Donnell, Mastercard

Paul Lucas, IBM

Richard Brown, R3

Sarah Meiklejohn, IC3

Sean Mullaney, Stripe

Simon Bray Shaw, ASOS

Vikram Kimyani, Oracle

Will Drewry, Google

Observers

HM Treasury

National Cyber Security Centre