Quote from: Syke on October 15, 2014, 05:51:07 AM

Quote from: NewLiberty on October 15, 2014, 12:18:33 AM

The cost is not that significant. Heck, the whole BTC market cap is not that significant.

If there were 6 GB block size bloat per hour?
A financial attack could do this independently.
Miners could do this free-ish.
Small miners would fail, as would all hobby miners.

Full nodes would become centralized, increased 51% risks, etc.
These are just the obvious. No more decentralisation for Bitcoin.

From the wiki:

Quote

Note that a typical transaction is 500 bytes, so the typical transaction fee for low-priority transactions is 0.1 mBTC (0.0001 BTC), regardless of the number of bitcoins sent.

To spam the 1 MB blocksize takes roughly .2 BTC per block, or 1.2 BTC per hour. That's only $500 per hour.

To spam a 1 GB blocksize takes roughly 200 BTC per block, or 1200 BTC per hour. That's $500,000 per hour!

A 1 GB blocksize is far more costly to attack. We could increase the blocksize to 1 GB now and nothing would happen because there aren't that many transactions to fill such blocks.

I didn't see if this was addressed elsewhere already...
The projected attack would come from a mining concern that is looking to shut out smaller players and consolidate their mining regime.
The cost of the attack is the marginal cost of a winning block being orphaned. The transaction fee is paid by and to the attacker, at no cost.

However if it is not orphaned, the reward is significant. While the block is being downloaded and verified by lower bandwidth nodes, the "attacker" is already at work on the next block, and with some decreased competition has some advantages. It is essentially a denial of service from larger bandwidth miner to lesser bandwidth miner.