BIS unveils CBDC prototype balancing privacy and regulation

The Bank for International Settlements (BIS) has released a report detailing a prototype for a Central Bank Digital Currency (CBDC) that aims to balance cash-like anonymity with regulatory compliance. Developed by the BIS Innovation Hub Hong Kong Centre in collaboration with the Hong Kong Monetary Authority, Hong Kong Polytechnic University, and the Hong Kong Applied Science and Technology Research Institute (ASTRI), the project explores how digital currencies can protect user privacy while preventing money laundering and terrorist financing.

The prototype utilizes three core cryptographic technologies: BBS+ signatures to generate pseudonyms, zero-knowledge proofs (ZKP) to verify transaction validity without revealing sensitive data, and encrypted ledgers to separate bank records. This design ensures that while third parties cannot track transaction histories, authorized banks can still perform identity verification (KYC) and comply with legal requirements when necessary.

Despite the technical progress, the BIS noted that the technology is not yet ready for practical implementation. Key challenges include the high computational load required for generating zero-knowledge proofs, which can cause transaction delays, and the risk of permanent fund loss if users lose their private keys. The report serves as a research foundation for central banks considering the design of future digital currencies.