Well I'm not sure what you just said is any less complex, it certainly confused me. But if what you are saying is valid, you are claiming that a small change to the existing Bitcoin protocol can basically provide something similar to a finite mini-blockchain? I'm certainly very skeptical about that, I don't think my system is overly complex, I believe it has the minimum components required to make the mini-blockchain scheme secure and robust.

I actually took a look at your thread a few hours ago and your idea seems fairly complex. I would recommend writing a white paper or something. While I agree it may be beneficial to mix together as many good ideas as possible it's still problematic. At this point my goal is simply to just implement this mini-blockchain scheme to see if it actually works. The job is already difficult enough and I don't want to go including all these other untested ideas, it will just make the process longer and harder. As I said, the goal of this project is really just to stay as close to the bitcoin protocol as possible and just play it safe. I would recommend the same thing with your project as well, first just build it as you imagine it and see if it actually performs as you believe it will. When you try to start off with too much on your plate it can often lead you to troubles. At some later point maybe we can have a mini-blockchain + PoS + your exchange model (although I'm still skeptical of the PoS stuff and I'd need to understand your proposal better for actually backing it), but right now that isn't the best course of action to take in my opinion.

What is this project all about?

The goal of this project is to implement a new crypto-currency protocol designed to solve the "blockchain bloat" problem once and for all by replacing the full blockchain with a finite "mini-blockchain". Such a system would offer many benefits including consistently fast synchronization times, much more block space, faster transactions, and lower fees. Certainly not an easy problem to solve, but if it could be solved we are looking at truly new and unique improvements over the Bitcoin protocol.

We now believe that this problem finally has been cracked. The concept and technical details of the proposal can be found in the white paper (a little outdated now) and the project wiki. This new scheme has been analyzed by many intelligent people and we haven't found any major flaws. After a considerable amount of feedback, myself and several others are convinced the scheme is viable and we want to attempt an implementation.

Our objectives and approach

The main objective of this project is to bring together many new ideas and concepts while staying as true to Bitcoin as possible. This project will attempt to minimize and exclude any controversial proposals and ideas but remain open to new and experimental proposals which we believe could enhance the final system. We aim to take the safe and trusted route ever possible and avoid over-complicating the scheme by bringing together too many different ideas.

The main focus of this project is to implement the mini-blockchain protocol and show that it works before we do anything else. If or when that goal is achieved we will start looking at incorporating several other experimental concepts which have the potential to provide an array of new features and benefits. Some examples of such concepts include secure 0-confirmation transactions based on a withdrawal limit system and a dynamic max block size.

Since we are trying to avoid any controversial and unnecessary complications, that means no pre-mine and probably no PoS integration. The PoS system is controversial in a way because it appears to make the rich richer over time and the benefits of such a system really aren't observable for a long time anyway. Not to mention the mini-blockchain proposal is already complicated enough as it is, keeping things simple is the key here.

The next generation of crypto-currency

What is the next generation of crypto-currency and what separates this project from any other alt coin? Most of you will agree that 95% of the alt coins out there are essentially pump and dump scams which offer nothing new or useful. I would personally say there are less than half a dozen alt coins which shouldn't be labeled scam coins; Namecoin, Devcoin, PPCoin, Novacoin, and Litecoin, and perhaps 1 or 2 other alt coins. I'm not so sure about PPCoin and Novacoin but they do offer new PoS features.

Litecoin doesn't really offer much beyond faster block confirmation speeds and scrypt-based mining, but since it was one of the first alt coins to offer these new features it has gained a genuine foothold in the crypto-currency market. Not only does this project offer a new coin with unseen features, but those new features are not small or trivial. Imagine always being able to download the blockchain within seconds or minutes as well as significantly faster transaction speeds.

Why am I making such a big deal of this? Well consider threads like this:
WARNING! Bitcoin will soon block small transaction outputs
New video: Why the blocksize limit keeps Bitcoin free and decentralized

All this concern over max block sizes, the SD "spam dust", the transaction capacity reaching its limit, all of this is nicely solved with a mini-blockchain + account tree implementation. Now I'm not saying Bitcoin is obsolete or outdated or that this new scheme will replace it, Bitcoin still has certain advantages over the mini-blockchain scheme and vice versa. However if this scheme turns out to work it does have the potential to seriously compete with bitcoin.

It was only a matter of time before someone was able to improve on the Bitcoin protocol and offer a new coin with highly desirable advantages over the original protocol, but I don't think that will mean the original will ever die out. Just because this scheme can offer more scalability and speed doesn't make it better as a tool for storing wealth. It does sort of make it better as a currency though, which is really what we should be aiming for I believe.

So how will the project be organized?

See: [BOUNTY] $20,000 Mini-Blockchain Implementation

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Project Address: 1AZjrg6h9nfvFt16kaszLTJkQi13kMwZz2

I'm aware of that, I'm simply saying these issues are of low priority right now, we should focus on getting a working prototype before we move onto branding etc.

I read your introduction post but not much else. You seemed to be referring to it as RoyalCoin in the opening post. Has that changed now or did I read it wrong or something? EDIT: sorry I see now I was reading it incorrectly. Good to know.

I honestly do not care if this coin lurks around in the shadows for a while, the long term benefits will clearly shine through and prove its worth and value. I have no intention of pumping it up at the beginning, there's no point because it will do perfectly fine without a pre-mine promotion or what ever it is you plan to do. I strongly believe a perfectly natural start is the best thing for the currency in the long term and my position on that will not change.

digitalindustry, I appreciate this thread but I have some issues with the approach.

1) Focus on non-essential issues (logo, coin name, etc)
2) It's not really going to be called RoyalCoin is it?
3) Your self-assigned role as project leader

You're free to start your own project which includes my scheme but I cannot be a part of that project unless you stop trying to control every important aspect of the project. Every aspect of the coin needs to be up for debate at this point and before we even get into things like the name and logo there are much more important things to deal with.

What we need right now is a development thread, the focus should be on creating a project repository and implementing the new ideas to see how they work. After the core work is complete, we can see if it appears possible and beneficial to include something like PoS into the scheme. The goals at this stage should be:

1) Implementing mini-blockchain and proof chain
2) Implementing account tree database
3) Modify transaction system to work with new scheme

We're still in the pre-development phase, we must keep all our cards on the table. All participants need to have an equal say. I do not like the idea of you deciding everything just because you think you know a thing or two about marketing and economics. If you choose to lead the project in such a manner I will not endorse it.

For one thing I will never agree to a pre-mine regardless of what its purported purpose is. It's simply not needed despite what you may believe or argue, there's no true justification for it because the this coin design offers so many new advantages and it will take off stronger than most alt coins out there, without a doubt.

Yes I agree you cannot really resort to consensus, that's why I said aaaxn's solution is probably the best. Simply don't give new nodes a chance to be tricked by the fake chain. This resolves the problem in a fairly neat way. Holding an entire year worth of transactions is still way too much when there's no real point. So far this is the only attack we've thought of which might provide incentive to increase the length of the mini-blockchain, but if we can eliminate the threat of this attack without having to do that then that's the way it should be solved. And we can with aaaxn's solution.

He is referring to a new vulnerability which is some what similar to the old issue but much more difficult to pull off and easy to prevent with the mechanism I've been talking about for the last 2 pages.

What do "lite clients" have to do with anything here? I'm not sure you understand the concept properly or that you've read the white paper properly.

The new nodes (not lite nodes) would be cut out of the picture. In no way would that shut down commerce, the legitimate older nodes would keep chugging along with the real chain and they wouldn't even pay attention to the fake chain. The fake chain wouldn't even affect anything unless you relied upon a node which was using the fake chain, which cannot happen if new nodes are cut out if the picture until the situation is resolved.

EDIT: or do you mean it may hinder commerce for a business who attempts to start up a new node at the time of this attack? Worse case scenario they have to wait until the attack is over to start their node, or wait until a new client is released with the updated checkpoint. It's not like the businesses already running a node would be affected.

You'll need to elaborate, I don't understand what you mean.

Yes that is a valid point but all the older legit nodes can still be trusted, there's no way the attacker can trick them. Not only would the attacker need a boatload of hashing power but also a boatload of IP's and bandwidth to out number the legit nodes. Of course that is still possible so perhaps the best method to solve this problem would not be a voting system but the solution aaxon suggested:


That pretty much seems like the best solution because it would cut new nodes out of the picture and leave the legit nodes to wear down the attacker until he gives up.

It doesn't know. That's why it's a vote system. The node assumes that the majority of votes will be from legitimate nodes. Of course that wont always be the case but it will be the case at least 80% of the time.

An attacker with enough power to outpace the blockchain for a day or more is obviously going to get away with something. Even in Bitcoin an attacker with that much power over such a long period of time could do a bit of damage. But it's still not a true form of double spending, it's a temporary illusion, and if the attacker had a hard time getting any other node to accept his fake chain wouldn't it be virtually impossible for him to achieve a double spend?

Probably pretty unfeasible. Even something like the "rolling chain" idea mentioned in the paper would be extremely tricky to implement with Bitcoin. I spent a lot of time thinking about ways the Bitcoin blockchain could be made much smaller but the only thing I could really come up with was to create a whole new crypto-currency.

I haven't really looked into it but Ripple appears to use some sort of pseudo-centralized solution. I don't think the coins were created in a decentralized way. And there was just a thread about a Ripple account being hacked because of a weak password or something. So the accounts even appear to be centrally managed.

With the solution I described in my last post, the attacker would only succeed if he convinced enough new nodes to accept his fake chain and together they could supply more hashing power to the fake chain than the older nodes to the real chain. While that seems virtually impossible it may be some what possible if the attacker continues to contribute hashing power even after tricking new nodes to accept the chain. Because obviously this attacker must have an ungodly amount of hashing power to outpace the real mini-blockchain for a full cycle.

One way to really drill the final nail into the coffin of this attack might be this: if a new node detects two full mini-blockchain's which both originate from the same proof chain it can simply resort to a peer vote system by asking older nodes which chain is the valid one. Legitimate older nodes who noticed the fake chain appear out of thin air would reply to the new node telling them not to trust the one which appeared to come out of no where. Now the attacker would have an extremely hard time getting enough slaves in on his little scheme.

Even if the attacker had a huge botnet at his disposal at least 80 to 90 percent of existing and new nodes would reject the fake chain and continue working on the real chain. Soon enough the attacker wouldn't be able to afford continuing the attack and he would give up. The real mini-blockchain would quickly overtake the fake chain once the attacker stopped contributing his hashing power to it. With these mechanisms in place the attacker has no hope of convincing more than half the network to use his fake chain.

Hmmm... I think I see what you are getting at here. The attacker generates a fake chain in the background using the real proof chain but a fake account tree. He outpaces the real mini-blockchain for a full cycle until there's no evidence left to indicate his account tree is fake and releases the fake chain.

That would be one hell of an attack to pull off and even after pulling it off there's a low chance the fake account tree would propagate enough to become the main account tree. But this just goes to show the mini-blockchain does need to hold at least maybe a week or more worth of transaction history.

Although I think one possible way to dramatically minimize the threat of this attack is to make it so a node who has been connected to the network for a while will only accept a different chain with more power if they know where the chain came from, that it didn't just pop out of thin air.

For example a node who has been validating blocks longer than the cycle of the mini-blockchain can simply ignore a new chain if it appears to that node as if the chain popped out of no where. This will still allow the normal process of block orphaning to occur because the chains do not pop out of no where in that case.

By the way CFB, what did you did think of the proof chain concept? Can you see any flaws in that idea? Honestly though it may be better to just start by using the block header system and then maybe try creating a proof chain system to see how it works at a later stage.

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I don't see why the client would be larger or more complex. Nothing described in the paper should really be too difficult to implement, it's really just taking the bitcoin scheme and modifying certain aspects of it to remove the need for a full blockchain.

I don't believe so. If it did we could just use the block headers instead of a proof chain... I mean there's really no need to create a whole new proof chain system when we can use the block headers. But the proof chain mechanism probably would have certain advantages assuming it provided the same level of security as the block header system.

Well it's not that hard to come up with a great idea.
The hard part is making the idea work.
Thanks for taking a look.

I've been working on this idea for a few months now but I couldn't get past the problem of making the scheme satisfactorily secure. I finally solved that part of the puzzle about a week ago and immediately decided that I needed to write a white paper and formalize the concept some what.

I also want to give an acknowledgment to member aaaxn for helping me fine tune some of the concepts in the paper, his knowledge was very helpful. Until now no one else has read this white paper so I'm hoping for a lot more great feedback from other members.

NOTE: the white paper is now fairly out-dated. Check the project wiki for more up-to-date information concerning the mini-blockchain proposal.

Purely P2P Crypto-Currency With Finite Mini-Blockchain (PDF)


Project development thread: https://bitcointalk.org/index.php?topic=215936.0