Hello friends i am much worried ...
2 days ago one exchanger send me btc but still not confirmed.Few minutes ago my transaction had reversed back to exchanger account.
what is a double spending attack or not?
and how payment reversed.and now a time double spending attack is possible?
Say goodbye to that money. Gone. Sorry about the bad luck.
This is how double spend works. They set up a transaction (first spend), then when it falls as unsuccessful, they spend the same money on a different address/transaction (second spend).
The first transaction 'didn't happen' like the guy said above. Therefore, you are out of your money and fucked.
Bitcoin is very complex. Most people just get robbed and then quit. Please be careful. Anyone can just log in to your computer and get all your savings in an instant.