국제간 디지탈 화폐 소액 결제 시스템 구축 방안(23.3月)/BIS
=Breaking new paths in crossborder retail CBDC payments=
While domestic payments have seen significant improvement in many jurisdictions in recent years, cross-border payments still face challenges such as high costs, low speed, limited access and insufficient transparency.
The G20 has made it a priority to enhance cross-border payments and, in response to this call for action, the BIS Innovation Hub is coordinating experiments on how this might be done.1, 2 Many central banks are exploring retail central bank digital currencies (rCBDCs). Some of these projects are at the proof-of-concept (PoC) stage, while others are in pilot trials and a handful have reached more mature phases.3 The requirements for interlinking these (domestic) rCBDC systems to support cross-border payments should be considered at the outset so that cross-border payments can be enabled when appropriate. Project Icebreaker explores a specific way to interlink rCBDC systems (the hub-andspoke solution) with several additional features that would allow the Icebreaker model to be readily scaled up.
In addition, these features would promote simplicity and interoperability, reduce settlement risk, and foster competition and transparency for cross-border rCBDC payments.4
Settlement risk and speed.
In the Icebreaker model, a cross-border transaction is broken up into two domestic payments, one in each domestic system. An rCBDC therefore never leaves its own domestic system. This is because FX providers buy one currency in one system and sell the other currency in the other system. An FX provider therefore holds rCBDC supporting wallets in two or more systems. Settlement is via an atomic payment-versuspayment (PvP) arrangement using Hash Time Locked Contracts (HTLC), which can be thought of as similar to a digital escrow. This eliminates the time gap between payment initiation and settlement, going a long way towards eliminating counterparty risk in the FX transaction.
Competition and transparency.
In most existing cross-border payment systems, the end user is bound to its payment service provider (PSP) for FX service. In the Icebreaker model, the FX service and pricing are decoupled from the provision of rCBDC payment services. FX providers submit FX rates to the Icebreaker hub, which selects the best rate to be presented to the payer for each payment request. This lets the payer access competitive FX rates independently of the PSP providing the end user with a digital rCBDCsupporting wallet. Additionally, the risk of insufficient liquidity in the desired bilateral currency pair is mitigated not only by the presence of multiple FX providers, but also by using bridge currencies. This could have potential in promoting competition between FX providers and making FX fees more transparent for end users.
Interoperability and scalability.
The number of connections between rCBDC systems are kept to a minimum by the hub-and-spoke approach used for the Icebreaker model. The Icebreaker hub only routes payment messages and does not act upon them. The only information it acts upon is the data from FX providers, which are used when identifying and selecting the best FX rates for the payer.
The Icebreaker model makes a minimal set of technical requirements about the rCBDC systems that connect to it, namely that:
• Each must be a functioning payment system and operate in real time, or near real time, ideally 24/7/365.
• Each can implement and support the use of HTLC.
• There are participants in each rCBDC system that can act as FX providers.
The Icebreaker hub provides a standard set of application programming interfaces (API), enabling different domestic systems to communicate with it seamlessly. The technological requirement on domestic systems is deliberately kept to a minimum, thus promoting scalability, interoperability and simplicity.
The project focused on core features only, including the technical solution for the Icebreaker hub, the integration of the three PoC rCBDC systems of Israel (Ethereum Quorum), Norway (Hyperledger Besu), and Sweden (Corda), and the technical validation of a limited set of key use cases, together with related policy considerations.5 Functional aspects such as AML/CFT, or longer-term considerations such as the business model or scheme rulebook were deemed out of scope but could be considered in future experimentation.
Project Icebreaker shows that central banks can have almost full autonomy when designing their domestic rCBDC system while still being able to participate in a formalised interlinking arrangement to enable cross-border payments.
The key recommendations for a central bank considering enabling cross-border payments in an implementation of a rCBDC system are to:
o Consider ways to incorporate conditional settlement, eg HTLC.
o Consider ways to ensure system availability and short response times 24/7/365 to maximise speed and minimise failed payments.
o Consider adopting current messaging and addressing standards and ensure flexibility in adopting future standards.
o Consider ways to provide instant rCBDC liquidity for FX providers 24/7/365.
o Promote transparent and competitive incentives for FX providers.
Implementing the Icebreaker model in the real world would require a range of technology, policy and legal considerations to be addressed.
Policy considerations could include the governance arrangement, the viability of the business model, liquidity provision, privacy, AML/CFT compliance and monitoring, and payment initiation-related standards.
Legal considerations would include a sound legal basis for the Icebreaker hub type approach, as well as the potential for conflict of laws and regulations between connected rCBDC systems, and conflict resolution.
Technical considerations could include resilience requirements for the Icebreaker hub and participants in the rCBDC systems. Central banks should factor in such cross-border aspects into the design of their rCBDC systems to avoid creating unintended barriers for cross-border functionality.
The Icebreaker model could serve as a platform for introducing payments innovations (such as delivery versus payment and programmable money use cases) that countries could consider in the context of developing the cross-border capabilities of their CBDC systems.