☕ Happy Ecash Coffee Day!
Five years ago today, someone bought a cup of coffee with ecash on Bitcoin for the first time.
Here's the story of that coffee, and why it still matters.
October 3, 2021. Paralelní Polis, Prague, during the Hackers Congress.
@elsirion sat down with freshly written code and one goal: buy a coffee with bitcoin, privately.
After a bit of friction, the payment went through.
It was the world's first purchase using ecash on Bitcoin. He paid through MiniMint, the early Chaumian ecash federation that became
@Fedimint.
Eric tweeted about it. It was just a coffee, but, in this moment, ecash was transformed from a great concept that didn’t gain traction four decades earlier to a reality.
Some ecash history: In the 1980s, cryptographer David Chaum invented ecash (digital money that works like cash) using blind signatures. Ecash is private, fungible, and untraceable.
Chaum’s company, DigiCash, was ahead of its time.
DigiCash had a weakness, though: it relied on the centralised banking system, which left it with a single point of failure.
Approximately two decades later, Satoshi Nakamoto built Bitcoin, money that's private and permissionless. Ecash finally had a decentralised foundation to be built upon.
Hal Finney received the first Bitcoin transaction from Satoshi. He saw Bitcoin's potential, and also its limits. He predicted it would need layers on top to give users stronger privacy.
Ecash is Finney’s prediction in working code.
How ecash complements Bitcoin:
🔒 Privacy: blind signatures make payments untraceable
⚡ Off-chain: fast, cheap transfers that never touch the blockchain
🪙 Micropayments: small, everyday payments where on-chain fees would stifle spending
Since then, the ecash ecosystem has grown:
Fedimint spreads custody across multiple guardians, so no single party can steal funds, censor payments, or be pressured into censoring them.
Cashu started out by offering a single-mint model that's easy to set up and has begun working on a federated model (more on that a bit further down).
What is more, the ecash engineering community has begun to add a new layer of resilience for Fedimint users.
In September, Fedi CEO, nostr:nprofile1qqstqlfpduhsgghvqffdmqdx2yac6zcv0mu99y0m7k59au3l3hmclfcppamhxue69uhk2tnwdaejumr0dsq3vamnwvaz7tmgv5h8yetvv9ukzcnvv5hx7un870mmefcalled on the Fedimint developer community to create multiple implementations of the Fedimint protocol as a means to reduce reliance on a single codebase.
The developer community responded at Bitcoin++.
At a recent ecash hackday, Eric, Joscha, and a group of Fedimint developers created three new implementations of the protocol.
(And they challenged other developers to build a fourth.)
Plus,
@calle, creator of Cashu, recently shared his new “Federated Cashu” model, which includes a Blind BLS signature scheme.
The push for privacy continues beyond federated ecash, as well. Projects and protocols including Lightning, BitVM, Ark, PIPES, Silent Payments, WabiSabi, CoinSwap all can provide users with greater privacy.
Across Bitcoin, more and more builders agree that privacy can't be optional.
The stakes are real. People living under authoritarian regimes already use ecash, as do activists and journalists under surveillance and families who just want to pay safely and with anonymity.
We’ve seen this highlighted in the work that HRF does.
Without privacy, Bitcoin is open to coercion. With it, Bitcoin is a lifeline.
We started celebrating Ecash Coffee Day in 2024 to mark the 3rd anniversary. Since then, it has moved from a celebration to a call for action.
Until Bitcoin has reliable privacy by default, for everyone, everywhere, the work isn't done.
So grab a coffee today ☕. Pay for it privately via the Fedi app or another app that supports private payments if you can. And recommit to building, funding, and supporting privacy tech.
Paying privately is a basic human right.
Happy Ecash Coffee Day 🧡
