Quote from: DjangoSi on November 27, 2015, 10:33:23 AM

Hey,

I am searching for a way to create a double spend for an existing transaction.
- snip -
how to do it?

What wallet was used to create the original transaction?

Depending on the wallet you used to send the first transaction, it might be possible to generate a a "double-spend" attempt without much technical knowledge.

If with some technical knowledge and, access to the private keys, you can generate a "double-spend attempt" regardless of which wallet created the original transaction.

For the transaction you indicated, the technical way to generate a "double-spend attempt would be to build, sign and broadcast a raw transaction that uses the same inputs. For example using Bitcoin Core you could build the raw transaction like this:

Code:

createrawtransaction '[{"txid":"cf6ea1b14f27195a69665d8961118dfd8e9d19d946764d67345ba31d622d981a","vout":1},{"txid":"b03cc102d4f722bcf7b237feb799ed602e0cc3cc945a4d30f6eb861f241d32ff","vout":0},{"txid":"1011c64dc8f6906a79bc39aebcb8945d1b63ce0e4444b7e49c25773da31ec1b7","vout":0},{"txid":"044a8b94bdc27356867421e041967761ff7f43ade89563af85e277f7ae8803e1","vout":0},{"txid":"5668339c29860f373548d13eb03cb7a14fd1c49ff393bd1dfc223fc8a27984c6","vout":0},{"txid":"77526f1a661b3788cda260e1d8a34ff1be30cfa23becae6c9ac1ccc0ce97c166","vout":1}]' '{"1Pceqe652xmvAK6vDxcoD59yCdZ8G9pfXn":0.88795802}'