Ecash on Bitcoin
Cashu open source contributor
What is ecash?
How does it work?
Why is it useful?
[1983] (Chaumian) Ecash is a an electronic cash system that uses:
- A blind signature scheme
- A centralized signing/verifying instance
- and Bearer tokens
To replicate the properties of physical cash in the digital realm
What is ecash?
A better custody system
What is ecash?
A better custody system
IOU (backed by something)
IOU (backed by something)
What is ecash?
A better custody system
IOU (backed by something)
IOU (backed by something)
What digital payments should've been
What is ecash?
A better custody system
IOU (backed by something)
IOU (backed by something)
What digital payments should've been
Bitcoin "Layer"
What is ecash?
A better custody system
IOU (backed by something)
IOU (backed by something)
What digital payments should've been
Bitcoin "Layer"
Scaling solution for Bitcoin
What is ecash?
A better custody system
IOU (backed by something)
IOU (backed by something)
What digital payments should've been
Bitcoin "Layer"
Scaling solution for Bitcoin
A solution for every problem
What is ecash?
What is ecash?
No Ledger
Distributed Ledger
What is ecash?
No Ledger
Distributed Ledger
Bearer Token
UTXO
What is ecash?
No Ledger
Distributed Ledger
Bearer Token
UTXO
Public transactions
Blinded transactions
What is ecash?
No Ledger
Distributed Ledger
Bearer Token
UTXO
Public transactions
Blinded transactions
Decentralized Blockchain
Centralized verification
What is ecash?
No Ledger
Distributed Ledger
Bearer Token
UTXO
Public transactions
Blinded transactions
Decentralized Blockchain
Centralized verification
Trusted
Trustless
What is ecash?
No Ledger
Distributed Ledger
Bearer Token
UTXO
Public transactions
Blinded transactions
Decentralized Blockchain
Centralized verification
Trusted
Trustless
Ephemeral transactions
Eternal transactions
What is ecash?
No Ledger
Distributed Ledger
Bearer Token
UTXO
Public transactions
Blinded transactions
Decentralized Blockchain
Centralized verification
Trusted
Trustless
Ephemeral transactions
Eternal transactions
|
|
|---|
How?
"Traditional" custodial setup
Alice
Bob
Charlie
Alice
Bob
Charlie
| Sender | Amount | Receiver |
|---|---|---|
| Alice | 10$ | Bob |
| User | Balance |
|---|---|
| Alice | 20$ |
| Bob | 10$ |
| Charlie | 0$ |
Alice
Bob
Charlie
| Sender | Amount | Receiver |
|---|---|---|
| Alice | 10$ | Bob |
| Bob | 5$ | Charlie |
| User | Balance |
|---|---|
| Alice | 20$ |
| Bob | 5$ |
| Charlie | 5$ |
Alice
Bob
Charlie
Authorize
What's wrong?
- Horrible privacy
- Easy to target/censor individuals
- Data honey-pot
Ecash custodial setup
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
Only Alice can open
Carbon paper
| Spent secrets |
|---|
Alice
Bob
Charlie
secret
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
Alice
Bob
Charlie
| Spent secrets |
|---|
No Ledger
Bearer Token
Blinded transactions
| Spent secrets |
|---|
No Ledger
Bearer Token
Blinded transactions
cryptography
Cashu use cases
Peer to peer payments
Offline payments*
Peer to peer payments
Provide LN infrastructure to users
Advanced use cases
HTLCs
"Smart Contracts"
Blinded authorization
Why I think ecash is important?
- Empower users (smart client, dumb server)
- Restore balance and responsibility in the way we use services online
- Provide an alternative to the "account-model"
Thank you!
npub1cj6ndx5akfazux7f0vjl4fyx9k0ulf682p437fe03a9ndwqjm0tqj886t6
Let's keep in touch on nostr