I have written before (eg, here in Forbes) that one of the great attractions of building a new digital cash infrastructure to implement a digital currency, instead of just laying a simple peer-to-peer protocol on top of the existing digital money infrastructure, is that it would add to diversity to the infrastructure and therefore resilience to the payment system, which is vital national infrastructure.
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DCash — the digital currency used by seven Caribbean nations — has been down for the last two weeks and it’s unclear when it will be back online, the Eastern Caribbean Central Bank said Friday.
From Caribbean Digital Currency, DCash, Remains Offline for Second Week.
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It’s not just that CBDC must work offline, but that it must work independently from he existing electronic money infrastructure.
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Many Kazakh citizens rely on traditional digital payment methods like debit cards to buy food, but without internet connections, these were rendered useless. Local media have reported long queues for ATMs and withdrawal caps because of shortages of cash.
For central banks, the situation in Kazakhstan shows both the importance and the limitations of cash. The crisis makes it clear that it will not be enough for central banks to develop an online digital currency transaction network while treating cash as the offline back-up.
From Kazakhstan unrest highlights importance of offline payment functionality – OMFIF.
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This one of the aspects of digital currency that fascinates me. Some innovative thinking will required to deliver a genuine cash alternative into mass markets and my strong suspicion is that it will depend on the use of secure, tamper-resistant hardware. Writing [here a year ago], Vipin Bharathan talked about Visa’s proposed Offline Payment System (OPS) which implement digital currency using digital signatures generated in this hardware, in the form of Trusted Executions Environments (TEEs) in mobile phones and laptops and so on. This is only one of the solutions being proposed but it illustrates the general class of most-likely implementation rather well: since these chips cannot be cloned, they provide a means to prevent the subversion of transactions even when they are device-to-device with no blockchain or database in sight.
These TEEs are chips (just the like chips on bank cards or the SIM cards inside mobile phones) that cost next to nothing.
China