Topic: We need your help! (Read 419 times)

Ok, thank you!

Depends on your wallet...
For example, if you use electrum, you can enable coin controll, pick one (or multiple) unspent outputs from the coins-tab, right click, spend, enter a receiving address and a very low fee (you need to enable manual fee selection to).
When you created your transaction, click on the "preview" button instead of the send button, then sign the transaction and save it (do not broadcast). Close the window
In the next step, select exactly the same unspent outputs, spend, enter a different receiving address, enter a much higher fee, preview, sign, save.

You now have 2 unbroadcasted, signed transactions that spend the same unspent outputs.
Theoretically, the one with the lower fee/byte ratio has less chance of getting confirmed. However, there is no guarantee. The second transaction (with the higher fee/byte ratio) will usually not broadcast so good as the first one (since the first transaction will already be in the mempool of many nodes).

If you use core, you can create a double spending tx from the cli or from the debug window... You'll need to use following commands:
- listunspent
- createrawtransaction
- signrawtransaction

It's all pretty basic stuff... You should learn these basics before attempting to build a paywall. Also, there is hardly ever a reason not to develop on the testnet. I've had a client lately that insisted on testing on the main net to, we've lost a lot of money due to high transaction fees without any reason

How can we make double spend transactions? Can anyone explain? We have spent all btc in the devolpment, we have only 0.0004btc 

Any transaction with low fee will do. Try zero fee, it may never confirm.
Next step will be to double spend it, I've done it in the past to get rid of unconfirmed transactions.

For a pay wall, I expect low amounts, correct? You can require 1 confirmation if a low fee is used.

If the amount is low enough to be considered dust (say $0.50), it may not be worth the fee you need to spend it again. If that's the case, you're not earning anything from it.

We would like to test it in the real bitcoin network.

If it's only for testing, why don't you move your project to the testnet?
If you're going to accept 0-conf transactions, you're going to get "robbed" (people will figure out how to download your product for free, it's not hard to double spend unconfirmed inputs from a transaction, as long as the transaction itself is unconfirmed).

Hi,
we are developing a bitcoin paywall.
for the optimal ease of use, you need no confirms to get the product. There is an exploit. To get the entire product free. Can anyone help us to generate such transactions?
or can anyone give us a instruction how we can create fake Transactions?
Thanks in advance!
Greetings Form Germany!
DISCLAIMER: IT'S ONLY FOR TESTING.