6 confirmations is not enough

[AtheistAKASaneBrain]

Because the have an investment directly to the success of bitcoin, (if transactions are double spent, bitcoin becomes less valuable and asic miners become junk) they will follow the honest road and not try to rewrite the history.

We just need a few altcoins with SHA256 mining algo to solve this issue.

Most altcoins refuse to use SHA256 to be different, its a gimmick really, all these stupid different algos are just a fad.

[MrTeal]

As another scenario, if you actually could get 50+% of miners to agree to a scheme like this, why wouldn't you just have them start mining their own blocks and not including any blocks from other miners? They could maintain the longest chain at no cost to themselves, and once the difficulty drops substantially due to the blocks from the other 45% or so of miners not being included they would effectively be almost doubling their income (in BTC) at no cost. That would give them massively more than a couple hundred BTC.

Interesting. Any ideas why we don't observe this right now?

I don't think anyone answered this

Because a couple large players effectively strong-arming anyone else out of the mining business would effectively destroy the value of Bitcoin. This is not just a hypothetical attack, LukeJr did just such an attack on an alt coin by merge-mining it with Bitcoin but not including any other blocks and not including any transactions. It killed the target altcoin. The difference there was that there was effectively no cost to kill CLC, as it was possible to do so without expending any resources. Eligius mined only Bitcoin and Namecoin, and Luke was able to simply use the results of those hashes to attack CLC without causing any economic cost to the users of Eligius. He essentially had a free supermajority of the CLC hashing power.

To attack Bitcoin directly in that way, you would need to directly use the majority of Bitcoin hashing power, the difference that it has a cost of hundreds of millions of dollars and no real use outside of performing Bitcoin-style double-SHA. If you did this you would effectively be betting that going from ~BTC1800/day to BTC3600/day by forcing out your rivals more than offsets the depreciation in your equipment and the decline in the value of each bitcoin you mine. The attacking group would effectively be making a hundred+ million dollar bet that no one cares they've taken exclusive control of Bitcoin transaction processing. To date, there hasn't been an entity that is both that rich and that stupid.

[OrientA]

Because the have an investment directly to the success of bitcoin, (if transactions are double spent, bitcoin becomes less valuable and asic miners become junk) they will follow the honest road and not try to rewrite the history.

We just need a few altcoins with SHA256 mining algo to solve this issue.

If the alt coins were able to pick up the slack from all the asics and be profitable enough for miners to take the bribe on bitcoin, then yes, there is a problem there.

Bitcoins core security relies on the fact that mining hardware can pretty much only be used for bitcoin, if anyone can think of a good use for trillions of sha256 hashes, then bitcoins security would go down greatly.

Seems weird that bitcoins security relies on buying miners that only work for bitcoin, PoS just simplifies the process from a mining device investment to an investment in the currency itself, but that's a little off topic

If BTC adopts multiple algorithms like Digibyte, will it become more secure?