<p>In one word: <strong>no</strong>. Changing tx output after signing makes existing signature invalid.</p>

<p>( There are some special cases, like signature hash type SIGHASH_SINGLE or SIGHASH_NONE, but we assume that the buyer uses correct signing SIGHASH_ALL )</p>

CC BY-SA 3.0
2015-04-01T18:13:16.063Z
There's nothing more correct about SIGHASH_ALL than other signature types.
Matthieu
CC BY-SA 3.0
2015-04-01T16:54:34.923Z
2015-04-01T16:54:34.923Z
amaclin
<p>In step 5 of the procedure described in <a href="https://en.bitcoin.it/wiki/Smart_Property#Theory" rel="nofollow">https://en.bitcoin.it/wiki/Smart_Property#Theory</a>, the buyer creates a partially signed transaction. Will the seller be able to change an output prior to signing and broadcasting - and thus returning the token to an output he may redeem himself?</p>

<transactions><raw-transaction><smartcontracts>
Is it possible to change an output of a partially signed transaction?
bitcoinbob
# Is it possible to change an output of a partially signed transaction?

(Asked by: username_0 on 2015-04-01)

In step 5 of the procedure described in <https://en.bitcoin.it/wiki/Smart_Property#Theory>, the buyer creates a partially signed transaction. Will the seller be able to change an output prior to signing and broadcasting - and thus returning the token to an output he may redeem himself?

**Tags:** transactions, raw-transaction, smartcontracts


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## 1 answers

### Answer by username_1 on 2015-04-01. Score: 2

In one word: **no**. Changing tx output after signing makes existing signature invalid.

( There are some special cases, like signature hash type SIGHASH\_SINGLE or SIGHASH\_NONE, but we assume that the buyer uses correct signing SIGHASH\_ALL )

> **Comments:**
> **username_2**: There's nothing more correct about SIGHASH_ALL than other signature types.  

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