BIS Innovation Hub publishes guide on offline CBDC use

The BIS Innovation Hub Nordic Centre has published its Project Polaris: Handbook for offline payments with CBDC, a handbook to guide central banks on implementing offline payments with CBDC.
Offline payments are defined as transfers of CBDCs value between devices without ledger system connection. The handbook highlights the importance of providing offline payments with CBDCs, but emphasizes that there is no one-size-fits-all solution as each country has multiple reasons for implementing it.
The handbook provides main reasons and usage scenarios for offline payments, as well as a map and an explanation of technology components. It also offers a set of design criteria for risk management, privacy, inclusion, compliance with AML/CFT regulations, and resilience, and provides considerations that central banks can use to inform their planning, policy development, technology and business requirements, procurement activities, and future operations.
The handbook emphasizes the need for policies and processes to be developed for risk parameters and how they are applied in normal and certain resilience scenarios. Further work is needed on interoperability and risk management systems for offline payments, and practical security-focused experiments addressing one or more of the threats listed in the handbook would be beneficial.
The roles and responsibilities of actors involved in a CBDCs payments ecosystem should be clearly defined, and collaboration between the public and private sector would be necessary. Security and operational requirements should be taken into account during the earliest stage of design, though any implementation should be kept as flexible as possible to accommodate any progress at the technical level.