user6310: When you are looking at a Bicoin transaction in the block chain and it has inputs from multiple addresses is it safe to assume that those addresses are all controlled by the same person/organization/wallet software?
Here is an example of a transaction with 31 different input addresses
https://blockchain.info/tx/a6bffa6208c72412399997b0c504670662e259fd5ba50128d0e2823b739bd18b
If I have definitive proof that one of those addresses is associated with someone can I infer that the other 30 are as well?

user208: No.
In practice, it is likely, but in several more complex use cases, transactions can be jointly constructed.
For example CoinJoin implies combining both inputs and outputs from multiple people together into a single transaction to make it less obvious which outputs belong to whom.

6310: <p>When you are looking at a Bicoin transaction in the block chain and it has inputs from multiple addresses is it safe to assume that those addresses are all controlled by the same person/organization/wallet software?</p>

<p>Here is an example of a transaction with 31 different input addresses</p>

<p><a href="https://blockchain.info/tx/a6bffa6208c72412399997b0c504670662e259fd5ba50128d0e2823b739bd18b" rel="nofollow">https://blockchain.info/tx/a6bffa6208c72412399997b0c504670662e259fd5ba50128d0e2823b739bd18b</a></p>

<p>If I have definitive proof that one of those addresses is associated with someone can I infer that the other 30 are as well?</p>
 208: <p>No.</p>

<p>In practice, it is likely, but in several more complex use cases, transactions can be jointly constructed.</p>

<p>For example CoinJoin implies combining both inputs and outputs from multiple people together into a single transaction to make it less obvious which outputs belong to whom.</p>
