Bitcoin Forum

I was mining DGC but started noticing some of my mined coins turning from confirmed to "?".  Also, I've sent some coins to another address which aren't coming through.  I read that baritus has openly challenged the community to attack the coin, so is it really happening now?  How can I tell?

Doesn't look like it's being attacked.
http://www.coinchoose.com/ shows network hashrate and average over the last 24 hours. It was just over 700 MH/s a few hours ago, right now hovering just under that. If you see a big spike in that hashrate, it's either because it's being attacked or just suddenly popular (which will happen if/when profitability gets high).

As far as transactions changing, it might be an issue of the blockchain that rarely happens. If you close the client and restart it and they're back, it was just some odd peer syncing issue. If not... well, you're screwed out of whatever coins.

Actually, a 51% attack will generally not cause a spike in the hash rate.  The attacker is mining on his own network and if he's smart, will broadcast his longer chain when he is ahead by only a block or two.

Ok, so it will cause a 1% spike in hash rate...good luck noticing that.

Networks fine. Just tested it on dgcdice.com  :)

I'm not sure you know how a 51% attack works.  The network doesn't just die.  In fact, it is highly unlikely that anyone will even notice a 51% attack has occurred until the attacker decides to sell millions of non-existent coins on an exchange.

This was clearly demonstrated with Powercoin.

My answer was in response to network issues. He said coins were going ? and not coming through.

If OP received coins during a 51% attack, they can be reflected in his wallet - but the coins don't actually exist.  So when he tries to send them, they will never confirm.

OP:  Yes, those are symptoms of a 51% attack.  Should probably wait for word on this from the exchanges trading this coin before investing further into it.

Afaik, you can't make coins out of thin air with a 51% attack :/ You can only double-spend your own coins.

Yes, and reverse all transactions that took place during the 51% attack.

The attacker sends coins to an exchange, waits for 6 confirmations, then reverses the transaction.  The coins are now back in the attackers wallet but reflected in the attackers account on the exchange as well because of the way they are set up.

Now he has those coins in his wallet AND on the exchange.  He can keep repeating this until he has accrued millions of coins on the exchange, then sell the coin down to 0.00000.

This is basically the what I observed during powercoin attack. The confirmed transactions become uncomfirmed. If you are mining you barely pound a block even though you ought to received hundreds of blocks before the attack. And last the most damaging symptoms. Dumping of coins like the coins has no price. I also observed the network hash barely changed at that time.

seems likely that pools going down would be a first visible symptom? Nothing on that front.

Suffer, DGC suffered a long time ago, its already dead, people just think they can mine it and itll magically be valuable or something...

DGC is nowhere near dead, it is probably one of the best altcoins around and and has nearly 700MH/s on it constantly.

When I wish upon a star...

Yep its only just started. People who are writing it off will be sorry in a few months.