Is bitcoin irreversible while pending?

I've been using this currency to buy and sell my OSRS gold. Should I wait for the first confirmation like what popular gold sellers do? What does waiting for this first confirmation prevent from happening?

 

Yes, you should wait for 1 confirmation. Waiting for a confirmation prevents double spending.

 

What is this double spending?

 

Thanks for the reply, I read about it online and will be sure to do so for future trades

 

Double spending is just basically someone who is able to tick the same trade off which ends up in a double spend, very rare and very hard to pull off. Never seen anyone personally do it.

 

There are a couple ways, but all of them are very difficult to pull of and easy to thwart except for the 51%.

• Send two conflicting transactions in rapid succession into the Bitcoin network (known as a race attack).
• Pre-mine one transaction into a block and spend the same coins before releasing the block to invalidate that transaction (known as a Finney attack)
• Own 51+% of the total computing power of the Bitcoin network to reverse any transaction you feel like, as well as have total control of which transactions appear in blocks. This is called a 51% attack.

To prevent damages from the first attack - wait for one confirmation to appear on a given transaction. To prevent damage from the second attack - wait for 6 confirmations to appear on a transaction, or less if the transaction is small (but still require at least 1). Damage from the third attack can cripple the entire Bitcoin network, so don't worry about it - your business most likely won't be the main target (it's unlikely to happen without really big money getting involved).

 

I'll keep all of this in mind when I deal with BTC from now onwards, thanks!

 

chance of double spending is like 0.01% if u wait for like 15 secs

 

Most gold sites always tell me to wait for first confirmation before they can send their part so that's why I asked the question @Extrude I didn't think they'd do that if the chances were so slim

 

well if anything happens the gold site workers pay it out of their own pocket so yea they need to be cautious

 

No sent it cant be cancelled

 

Heard on some wallets people could turn there wallet "offline" which cancels the transaction. Must have been wrong about that then judging from what Xen said.

 

Really? Well I'll be careful in the future