BIS: Digital Cash Offers Privacy But Lacks Readiness

Digital cash can achieve cash-like privacy, but the technology stack is not yet production-ready due to risks such as bank data breaches, according to the Bank for International Settlements (BIS).

In its Project Aurum Phase 2 report published on Tuesday, the BIS outlined that the prototype implements a privacy-preserving digital cash architecture using the existing Aurum codebase. The project seeks a balanced approach between complete anonymity and full transaction transparency as central banks explore technical requirements for central bank digital currencies (CBDCs).

Data Breach Risks and Architecture

The BIS report indicated that compromising a single bank could potentially expose its customer data, but would not expose identities belonging to other counterparties. Furthermore, a validator-level compromise alone would not be sufficient to expose end users, the findings showed.

The research addresses ongoing scrutiny surrounding potential financial surveillance capabilities in CBDCs. Critics have previously flagged privacy and control concerns, pointing to pilots such as Brazil's central bank source code release in 2023, which revealed mechanisms enabling the freezing or reduction of user funds within wallets. In January, US President Donald Trump banned federal agencies from issuing a CBDC, citing similar stability and privacy risks.

Key facts

• The BIS published its Project Aurum Phase 2 report on Tuesday.
• The report states digital cash can achieve cash-like privacy.
• Compromising one bank may expose its specific customer data without affecting other counterparties.
• A validator-level compromise alone is insufficient to expose end users.
• Previous CBDC criticisms include surveillance and freezing capabilities in Brazil's pilot and a US ban on federal issuance.