Mike Caldwell (Casascius) proposed an idea in the ALT coin subforums last year which I feel could be revisited. It is something that could help Bitcoin and Litecoin both by protecting Bitcoin and giving Litecoin more intrinsic value at the same time. He didn't receive a lot of good feedback, but Litecoin wasn't on a 6 month downtrend at that time, so I feel they may be more apt to it nowadays. This would make Bitcoin more secure, and I propose adding another chain to protect Litecoin down the road adding 3 layers of protection from different mining hardware. As long as the 3rd, 4th, etc... coins were PoW with different hashing algorithms than the coins already in the chain, it can exponentially add protection to 51% attacks by making someone that wanted to do one have to buy/develop SHA256, Scrypt, <insert coin here since we all know ASIC proof algorithms don't really exist.. or at least if they do it is buried in the ALT subforum and it isn't general public knowledge yet.> ASICs. There is no reason why this had to be used with only ASICs, you could use coins with algorithms that can only be mined currently on GPUs/CPUs/FPGAs/Etc.
I hope you guys are open to implementing this idea, as I think it is a great one. One of the best solutions to protecting against 51% attacks that doesn't seem like it would be too hard to implement.
I will quote Mikes' post here:
https://bt.irlbtc.com/view/176556.0Litecoiners: Idea to make Litecoin importance skyrocket in Bitcoin ecosystem
Today at 07:20:47 PM
#1
Quick rant: I have always viewed Litecoin as a detraction from Bitcoin and have refused to make mass quantities of physical Litecoins as a result. I have viewed Litecoin as nothing more than a hedge against Bitcoin seeing a 51% attack due to choice of SHA256 as an algorithm.
But: I believe I have thought of an idea that would make Litecoin far more important and relevant in the Bitcoin/cryptocurrency ecosystem, by being as ready in wait as possible in case Bitcoin really does experience a 51% attack.
In a nutshell, I view a Bitcoin 51% attack as eventually possible, for one reason: ASIC production efficiency scales far more than linearly with the amount of money an actor is willing to put into it; a bad actor with $1 billion to 51%-attack Bitcoin with its own custom ASICs will be far more than ten times as effective than ten bad actors with $100 million.
Anyway: here is the idea: Add a mandatory merge-mining feature to Litecoin so that it is always "merge-mining" Bitcoins, just for pretend, in hopes that one day Bitcoin will have the option of "let's subscribe to the Litecoin chain" (as a secondary means of block validation) as a way to resolve a future 51% attack on Bitcoin's SHA256-based chain.
Here is sort of how it would work:
1. Add a new requirement to the Litecoin chain such that a valid Litecoin block must contain either a record of the most recent Bitcoin block header hash, or a repeat of the hash found in the prior Litecoin block (with a limit of repetitions). Litecoin blocks that contain outdated Bitcoin intelligence should be disfavored by nodes capable of detecting that. Further impose the requirement that Bitcoin block headers must be represented contiguously in the Litecoin chain - Bitcoin blocks cannot be skipped (which shouldn't be a problem, when Litecoin blocks happen 4x as often as Bitcoin)
2. In the event there is an active Bitcoin block chain fork, the requirement is loosened such that the Bitcoin block header hash requirement can be satisfied by any leg of the chain, not just the one Bitcoin considers valid.
3. Add a feature to Litecoin clients that allow Litecoin users to decide to prefer or not-prefer branches of a Bitcoin fork while one is in progress. The default for this should always favor the Bitcoin leg with the most longevity, and should disfavor long chains that suddenly appear to replace a large amount of the known Bitcoin block chain. The user/miner/pool-op should always have an easy way to have the final say, such as by pasting in a preformatted message either exiling or checkpointing Bitcoin blocks.
Anticipated benefits:
1. Bitcoin users would have a ready made remedy to a 51% attack that they can switch to: Bitcoin users can simply add the requirement that if a Bitcoin block header hash makes it into the Litecoin chain, that its proof of work should be given a bonus. Litecoin community could create and maintain pulls to the Satoshi client that cause it to subscribe to the Litecoin chain and incorporate it as intelligence toward block validation and resolving block chain forks.
2. Bitcoin would have an easy way to add an emergency upper bound to block creation, just in case an enormous amount of power suddenly appeared. By turning on an optional must-appear-in-Litecoin requirement, the Bitcoin community could switch on an upper bound of 1 block per 2.5 minutes if it was deemed necessary.
3. Litecoin would be seen as far more important than a wannabe bitcoin knockoff without added value by those who see it that way.
4. Bitcoin's blockchain would be re-democratized to CPU/GPU users without forcing the Bitcoin community to switch to scrypt, they'd have more decentralized influence on bitcoin than those with the means to buy/make ASICs
5. The legitimacy of Litecoins would increase greatly - people would see the value of Litecoins in their role of protecting Bitcoin, and would potentially vote for the longevity of Litecoin by offering to accept LTC for goods and services, thereby increasing their value.
6. I'd start making Casascius Litecoins if you guys did this and did it well.
I'd call the concept "marriage-mining". By doing something like this, LTC gives a nod to BTC's importance while adding synergistic value to BTC that LTC can benefit from by association.
I have brought it up in the Litecoin forums here:
https://bt.irlbtc.com/view/176556.0I am interested to hear Bitcoiners opinions about it as well. I initially didn't like the idea, but towards the end of the thread on Bitcointalk I realized it could be a very good thing for BOTH Bitcoin and Litecoin. I've been really hard on Litecoin lately trying to get them to up their game, I am hopeful that if the Bitcoin community wanted this 51% protection that they would be willing to make it happen.
