user5840: I am building a Bitcoin IPN to poll bitcoind every 5 minutes, find new payments with at least 1 confirm, and notify a server.
It looks like I am going to have to load them all up with 'listtransactions' every time and parse out new ones.  Inelegant, but I don't see any other option.
So the next problem is that I need a unique identifier of payments so that I can see if it has already sent a notice.  I have read that txid can change?  Well, that is not a bloody ID then, is it?!  How can I identify a payment?  sha1(address . amount . time) ?  What is the difference between 'time' and 'timereceived'? Are they static?
The best discussion I found about this is here but it doesn't look like it went anywhere;
https://bitcointalk.org/index.php?topic=3092.0
Cheers.

user1906: TXIDs cannot change. TXIDs are simply hashes of the transaction. It is possible for two different transactions to have the same TXID - that's called a hash collision. However, the chances of that happening are so low and I believe you will actually win prize money if you find a collision.

5840: <p>I am building a Bitcoin IPN to poll bitcoind every 5 minutes, find new payments with at least 1 confirm, and notify a server.</p>

<p>It looks like I am going to have to load them all up with 'listtransactions' every time and parse out new ones.  Inelegant, but I don't see any other option.</p>

<p>So the next problem is that I need a unique identifier of payments so that I can see if it has already sent a notice.  I have read that txid can change?  Well, that is not a bloody ID then, is it?!  How can I identify a payment?  sha1(address . amount . time) ?  What is the difference between 'time' and 'timereceived'? Are they static?</p>

<p>The best discussion I found about this is here but it doesn't look like it went anywhere;</p>

<p><a href="https://bitcointalk.org/index.php?topic=3092.0" rel="nofollow">https://bitcointalk.org/index.php?topic=3092.0</a></p>

<p>Cheers.</p>
 1906: <p>TXIDs cannot change. TXIDs are simply hashes of the transaction. It is <strong>possible</strong> for two different transactions to have the same TXID - that's called a hash collision. However, the chances of that happening are so low and I believe you will actually win prize money if you find a collision.</p>
