<p>If you read about Hal Finney's <a href="https://nakamotoinstitute.org/finney/rpow/index.html" rel="nofollow noreferrer">Reusable Proof-of-Work (RPOW)</a>, you'll see many similarities to UTXOs. RPOW was a prototype network where individuals created tokens using a similar PoW system to the one Bitcoin uses. These tokens could be signed over to other users (keys), just like bitcoin.</p>

CC BY-SA 4.0
2021-10-04T16:21:50.297Z
"In addition to allowing straight one-for-one exchanges of equal value, the RPOW server allows exchanges where tokens are split or combined in various ways. The rule is that the combined value of the new RPOWs must equal the combined value of the incoming POWs and RPOWs which are being exchanged." - That certainly sounds a lot like UTXOs! https://nakamotoinstitute.org/finney/rpow/theory.html
Maximillian Laumeister
CC BY-SA 4.0
2021-10-04T08:21:50.160Z
2021-10-04T08:21:50.160Z
Sachin Meier
<p>Did Satoshi invent the UTXO model (the concept of &quot;unspent transaction outputs&quot; that are spent fully when invoked, leaving new UTXOs and &quot;change&quot;), or was the UTXO model based on prior research or any prior system?</p>

<utxo><change><history><satoshi-nakamoto>
Did Satoshi invent UTXOs?
Maximillian Laumeister
# Did Satoshi invent UTXOs?

(Asked by: username_0 on 2021-10-03)

Did Satoshi invent the UTXO model (the concept of "unspent transaction outputs" that are spent fully when invoked, leaving new UTXOs and "change"), or was the UTXO model based on prior research or any prior system?

**Tags:** utxo, change, history, satoshi-nakamoto


---

## 1 answers

### Answer by username_1 on 2021-10-04. Score: 3

If you read about Hal Finney's [Reusable Proof-of-Work (RPOW)](https://nakamotoinstitute.org/finney/rpow/index.html), you'll see many similarities to UTXOs. RPOW was a prototype network where individuals created tokens using a similar PoW system to the one Bitcoin uses. These tokens could be signed over to other users (keys), just like bitcoin.

> **Comments:**
> **username_0**: "In addition to allowing straight one-for-one exchanges of equal value, the RPOW server allows exchanges where tokens are split or combined in various ways. The rule is that the combined value of the new RPOWs must equal the combined value of the incoming POWs and RPOWs which are being exchanged." - That certainly sounds a lot like UTXOs! https://nakamotoinstitute.org/finney/rpow/theory.html  

---

