Abstract
The last few years have seen a steep increase in blockchain
interoperability research. Most solutions connect public blockchains;
hence, the main cross-chain use case is token transfer. By-design
platform transparency, tamper-resistance, and auditability make
blockchains an infrastructure candidate for Central Bank Digital
Currencies (CBDCs), but bridging CBDCs is an important missing piece in
general. In this paper, we leverage an asset transfer protocol,
ODAP/SATP, to define an extendable and dependable blockchain
interoperability middleware that can bridge CBDC from Hyperledger Fabric
to EVM-based permissioned blockchains. The key interoperation enabler in
the solution is a shared asset definition enforced by both sides of the
bridge, accompanied by a mapping between Fabric Identities and Ethereum
addresses for Identity management. We implement our design for the CBDC
use case utilizing Hyperledger Cactus. Through a preliminary performance
evaluation, we show that the underlying ledgers heavily influence the
latency of the solution, not the bridging components.