<p>Bitcoin clients maintain a list of the current unspent outputs in a hash table.</p>

CC BY-SA 3.0
2013-05-05T16:13:26.037Z
2013-05-05T16:13:26.037Z
lurf jurv
<p>When a new block is being created, all the transactions must be verified. In order to do that, the outputs of the previous transaction must be found in the blockchain.</p>

<p>But the new transaction only refers to the previous transaction by a hash. How is that transaction located without searching the whole blockchain?</p>

<architecture>
How is the previous transaction found efficiently?
RentFree
# How is the previous transaction found efficiently?

(Asked by: username_0 on 2013-05-05)

When a new block is being created, all the transactions must be verified. In order to do that, the outputs of the previous transaction must be found in the blockchain.

But the new transaction only refers to the previous transaction by a hash. How is that transaction located without searching the whole blockchain?

**Tags:** architecture


---

## 1 answers

### Answer by username_1 on 2013-05-05. Score: 2

Bitcoin clients maintain a list of the current unspent outputs in a hash table.


---

