I've seen this in several topics and also on many other places, so I'd like to point this out again:

Common misconception. Bitcoin transactions are instant.

It's only the confirmations that take some time. But nowadays, for regular payments of 'normal' amounts (up to a few thousand $) it's completely safe to accept a payment as soon as it appears in the network (and has enough tx fee). You don't need to wait for any confirmation.

With todays network strength it's pretty much impossible (not to mention, way, WAY too expensive) to successfully forge a valid looking transaction (thus getting it propagated through the network) that doesn't get confirmed. Only in order to accept or trust payments for BIG amounts, e.g. when literally sending tons of money around, you better await a few confirmations.

So, in normal situations (with regular amounts), Bitcoin payments are already instant. NOT 10-60 minutes!

Hi kazimir,

First of all, merry Christmas.

Thanks for the update about the transaction speed. In fact, the under-the-bonnet technology is still a mystery to me. Do you happen to have a good (readable) link about it?

I want to understand the technology better. I lost .36 BTC with the Hashcows hack...

The one more thing was epic anyways people need to know how much Bitcoin transactions are fast !

BitPay has been using this algorithm on the Bitcoin network without any double-spending for quite some time..
here, read this:
 http://www.cryptocoinsnews.com/2014/02/13/the-mathematically-secure-way-to-accept-zero-confirmation-transactions/

Bitcoin Transaction are instant but for some reason like double spend seller mostly want 1 - 3 confirmation to confirm receive due to a lot of double spend .

If the transaction is sent with min fee and confirmed inputs, it is indeed very hard to double spend it even if it is unconfirmed.

The issue of tx malleability is completely a different thing.