Accepting 0-confirmation transactions and detecting double-spends with open source solution

I would like to accept 0-confirmation bitcoin for very small amounts. I am happy to accept zero-confirmation spends and am aware of the risks. However, the tool needs the ability to "flag" the accepted transaction/s if a double-spend is detected. I can then decide what action to take.

I do not want to use a centralized third-party tool. I would like to use something locally on the server. It would simply display pre-generated public addresses. No need for private keys and/or seeds to be on the server.

Does such a tool exist?

Thank you.

transactions

itshappening1

Posted 2014-10-01T08:41:40.800

Reputation: 31

I tried to clarify a title bit. Hopefully it is ok. – Mikko Ohtamaa – 2014-10-01T08:45:37.223

I would imagine you need to interact directly with bitcoind, but there are some wrappers. – Mikko Ohtamaa – 2014-10-01T08:46:02.613

Here is one: https://github.com/snitko/straight-server - you can try to fish out Bitcond wrappers for your favorite programming language on Github search. EDIT: Straight uses blockchain.info instead of Bitcoin network, so it is out of the question

– Mikko Ohtamaa – 2014-10-01T08:52:35.813

Answers

You should not interact with bitcoind, because it (current versions at least) filteres double-spend transactions

You should have your own network-sniffer solutution - the program which connects to the network nodes (as many as possible) and listens for all transactions, checking do they have conflicts with particular ones.

(How much would you pay for such program? Just interesting :) )

This is also not 100% safe solution - a miner can place double-spending transaction in block and mine it himself. Look here: https://bitcointalk.org/index.php?topic=327767.0

amaclin

Posted 2014-10-01T08:41:40.800

Reputation: 5 763

You can send a question to an owner of http://respends.thinlink.com/ Hope it helps

– amaclin – 2014-10-01T09:54:59.487

Isn't this: http://bitcoin.stackexchange.com/a/32636/14319 a way to detect double-spending through bitcoind?

– Doug Peters – 2014-11-20T18:52:41.787

Yes bitcoind filters double-spends. I am not aware of anything that can listen and detect double-spends. I too would be interested in this. I would imagine that a simple tool would be needed which just detects double-spends. You could then do as you wish with the tx ID and notify an existing payment application.

banker_delight

Posted 2014-10-01T08:41:40.800

Reputation: 1

Check out Bitcoin XT which is an early release version of functions that are proposed for Bitcoin Core. It relays double spends, and notifies the wallet of double-spend attempts that affect it.

You can hook up your own code to be run immediately when a double-spend is detected, using the -respendnotify option.

Tom Harding

Posted 2014-10-01T08:41:40.800

Reputation: 336