Sveriges Riksbank says more work is needed to tackle persistent problems in the design of offline central bank digital currency (CBDC).

“A secure and functional offline solution requires a lot of development work on technology,” the Swedish central bank said on March 20, after concluding the fourth testing phase of the e-krona.

During this period of testing, the central bank introduced a “shadow wallet” to enable offline payments between individuals and businesses. The Riksbank found that keeping