Abstract:In recent years, many major economies have paid close attention to central bank digital currency (CBDC). As an optional attribute of CBDC, dual offline transaction is considered to have great practical value under the circumstances for payment without network connection. This study proposes OAPM for CBDC, a dual offline anonymous e-payment scheme for mobile devices user as either a payer or a payee based on trusted execution environment (TEE) and secure element (SE). OAPM is suitable for mobile devices with limited resources. It allows payer to safely pay digital currency to payees without networking, without disclosing personal privacy information to payees and commercial banks, and without linking the payment behaviors of payers. Meanwhile, it allows payees’ devices to be offline. Regulators, such as central banks, can identify anonymous payers if necessary. The scheme satisfies a number of important attributes of digital currency transactions, including correctness, unlinkability, traceability, non-frame-up, confidentiality, authenticity, anti-double-cross, controllable anonymity, etc. Finally, the prototype system is implemented and the possible parameters are tested. Security analysis and experimental results show that the scheme can meet the actual needs of CBDC offline transaction of mobile users from both security and efficiency.