cbdc.study
a slow study of central bank digital currencies, in public
This is a quiet room on a high floor. Below us, a city is rehearsing the end of its working day. We have come here to think slowly about a kind of money that does not yet exist, and may not in the way it is presently described. Pull up a chair. The light is good for another hour.
p. 01A central bank digital currency, in the most patient description, is a claim against a central bank, denominated in the unit of account of its issuing state, settled on a digital ledger that the issuing authority retains the final word on. Everything else — what it feels like to spend, who can see, what it cannot do at three in the morning when the network is gone — is a design decision. Many of these decisions remain open. This site exists to keep them open while deciding them with care.
- token-based
- A bearer instrument, settled by transfer of an object whose authenticity is verified rather than by debiting and crediting an account. Closer in nature to a coin than a deposit. The reader is asked to hold the difference between “who you are” and “what you carry” for the rest of this page.
- two-tier
- An architecture in which the central bank issues digital currency but does not interact with the public directly; commercial banks and licensed providers take on distribution, identity, and after-hours support. The central bank's job remains — in the older sense — monetary.
- programmable money
- A phrase that has carried, over the last decade, both a promise and a warning. It can mean: money that obeys rules its issuer wrote. It can also mean: money that disobeys rules its holder cannot see. We use the term reluctantly, and never without a footnote.
How the issue actually moves.
On the right, a single-stroke ink diagram of the two-tier settlement. Watch it for a moment before reading on. The central bank issues a digital token; commercial banks take it; citizens receive it; commerce returns it to the banks; the banks redeem it against the central bank's ledger. Five steps. Nine seconds.
i. The central bank mints a unit. The unit is a claim against the central bank, not a deposit at it.
ii. A commercial bank takes the unit on behalf of its customers, against reserves it already holds.
iii. A citizen receives the unit. They can spend it; they cannot, in this design, easily print it.
iv. A merchant accepts the unit. Settlement is final, even before clearing.
v. The unit returns to the central bank, where it is extinguished, and the cycle closes.
“It must work when the network is gone. It must.”
A digital currency that depends on continuous connection has solved an easier problem than the one it pretends to solve. The harder question is what happens between two people who cannot reach the network — at the edge of a market, on a bus, in a typhoon. The honest CBDC must carry, in its smallest unit, a method for two devices to settle without a third. The history of money is largely the history of doing exactly that.
A garden with three walls.
Scroll slowly. Each ring peels back a level of disclosure. We do not start at the centre.
- i. The outer ring — anonymity. No identity is bound to the unit; the unit knows only itself.
- ii. The middle ring — pseudonymity. The unit knows a key; the key knows a person, but only under judicial process.
- iii. The inner ring — full identification. The unit and its holder are visible to a defined set of authorities at all times.
Most national designs sit somewhere between i. and ii. The promise of CBDC is to make the seam between these visible — to the public — rather than buried in a vendor contract.
The globe at dusk.
A cartogram of jurisdictions, drawn as hexagonal tiles that drift slightly as if blown by a soft wind. They lock only on hover. Click a tile to read where each country presently sits — pilot, retail, wholesale, paused, declined.
A small shelf of cited researchers.
Portraits below are stippled engravings, not photographs — paper-aged in the manner of a 19th-century scientific frontispiece, and faintly foxed where time has touched the page.
There is a single text link below. It is the entire conversion surface of cbdc.study. We will write to you four times a year, briefly, with what we have changed our mind about. We will not send you anything else.
Subscribe to the quarterly letter →Footnotes
- i. Published-before-conclusion is borrowed from the working-paper traditions of the BIS and various central banks.
- ii. BIS WP 1041 (2023). Offline payments with CBDC.
- iii. All Lottie animations on this page pause on
prefers-reduced-motion.