<p>Some hosted wallets are using addresses in elaborate ways. So you cant be sure the address sending the payment is the one "owning" the bitcoins.</p>

<p>An example is CoinJar, that uses addresses to indicate to what account the funds should be added. But behind the curtain CoinJar does anything it feels is best, making the most efficient use of all its previous outputs. </p>

CC BY-SA 3.0
2013-10-30T16:59:24.810Z
2013-10-30T16:59:24.810Z
Jonas Oestman
<p>Another reason is that it makes Bitcoin slightly more resilient to compromising ECDSA. Unused addresses, from which funds were never sent, don't expose their public key, so breaking ECDSA doesn't mean you can immediately spend the funds.</p>

CC BY-SA 3.0
2013-10-30T17:39:02.023Z
2013-10-30T17:39:02.023Z
Meni Rosenfeld
<p>One of the features of the <a href="https://en.bitcoin.it/wiki/BIP_0070" rel="nofollow noreferrer">new payment protocol</a> is that it allows the customer's wallet to automatically send a refund address with the transaction to the merchant.</p>

<p>Why would the refund not be sent back to the same address?</p>

<p>I read the <a href="https://bitcoin.stackexchange.com/questions/1629/why-does-bitcoin-send-the-change-to-a-different-address">related question</a> regarding why change is sent to a different address. Gavin and David Schwartz mentioned it being more difficult to track your bitcoin spendings and it obscuring which address is the spending address and which the change address. </p>

<p>Is this the reason why new addresses are supposed to be used for refunds or are there any additional reasons?</p>

<address><privacy><bip70-payment-protocol>
Payment Protocol: Is using different addresses for refunds just because of privacy?
Brian Fabian Crain
# Payment Protocol: Is using different addresses for refunds just because of privacy?

(Asked by: username_0 on 2013-10-30)

One of the features of the [new payment protocol](https://en.bitcoin.it/wiki/BIP_0070) is that it allows the customer's wallet to automatically send a refund address with the transaction to the merchant.

Why would the refund not be sent back to the same address?

I read the [related question](https://bitcoin.stackexchange.com/questions/1629/why-does-bitcoin-send-the-change-to-a-different-address) regarding why change is sent to a different address. Gavin and David Schwartz mentioned it being more difficult to track your bitcoin spendings and it obscuring which address is the spending address and which the change address.

Is this the reason why new addresses are supposed to be used for refunds or are there any additional reasons?

**Tags:** address, privacy, bip70-payment-protocol


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## 2 answers

### Answer by username_1 on 2013-10-30. Score: 2

Some hosted wallets are using addresses in elaborate ways. So you cant be sure the address sending the payment is the one "owning" the bitcoins.

An example is CoinJar, that uses addresses to indicate to what account the funds should be added. But behind the curtain CoinJar does anything it feels is best, making the most efficient use of all its previous outputs.


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### Answer by username_2 on 2013-10-30. Score: 2

Another reason is that it makes Bitcoin slightly more resilient to compromising ECDSA. Unused addresses, from which funds were never sent, don't expose their public key, so breaking ECDSA doesn't mean you can immediately spend the funds.


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