MC2: A cryptocurrency based on a hybrid PoW/PoS system

[tacotime]

Link to the draft version (0.05) of the whitepaper: Download

Notable things about this chain:
- Uses a new approach to secure hashing algorithms for the hash tree of a given block that should increase FPGA/ASIC resistance
- After 27 coin years it employs a system of voting to manipulate the interest rate of the block chain (users act as the central bank and regulate the rate of inflation)
- Difficulty is based on the linear weighted average of the block times for the past 18 days for PoW blocks
- New block reward adjustment algorithm is given that yields an 8% decrease in block reward per year
- Simple PoS design (tried to strip it of as many complexities as possible)
- PoW and PoS systems are designed to happily coexist, with favour slightly given to the PoW system
- PoS system also intended to prevent 51% attacks
- Coloured coins, e.g. for rewarding projects that you create arbitrarily
- Ledger system for regular coins that allows for a lightweight version of the blockchain instead of having to download the entire blockchain

Feel free to peer-review/tear it apart.  I will be the first to say that I'm pretty terrible at math, so please correct any mistakes I've made.  I'd love to hear why you think it's a great/terrible idea, though.  Obviously I anticipate there are a lot of problems with it that I couldn't foresee, so please help me out!

Official developer correspondence: dev {dot} mc2 {at} gmail {dot} com!

Freenode: #MC2!

[twelph]

Hmmm, all of these other awesome features implemented and simplified quite nicely, but no mention of improvement to confirmation speed? I'd even be happy with a modest 50-100% speed increase just to get enough confirmations for large purchases within the first 30 minutes. Thanks for your effort, looks promising so far!

[Benny1985]

Will be one to watch. Would it be Scrypt-based, or an offshoot of scrypt?

[tacotime]

Hmmm, all of these other awesome features implemented and simplified quite nicely, but no mention of improvement to confirmation speed? I'd even be happy with a modest 50-100% speed increase just to get enough confirmations for large purchases within the first 30 minutes. Thanks for your effort, looks promising so far!

Block rate is targeted to 30 blocks per hour, or six confirmations in twelve minutes.  For the first 90 days of the block chain, it will be 15 blocks per hour due to the absence of PoS and increase from there on out.  This is initially a little slower than LTC, then about about the same rate.

[tacotime]

Will be one to watch. Would it be Scrypt-based, or an offshoot of scrypt?

Heavily scrypt based (scrypt with four different secure hash algorithms and two different stream cipher algorithms for fault tolerance and ASIC resistance in arranged in the blockchain in a randomized order)

[twelph]

Hmmm, all of these other awesome features implemented and simplified quite nicely, but no mention of improvement to confirmation speed? I'd even be happy with a modest 50-100% speed increase just to get enough confirmations for large purchases within the first 30 minutes. Thanks for your effort, looks promising so far!

Block rate is targeted to 30 blocks per hour, or six confirmations in twelve minutes.  For the first 90 days of the block chain, it will be 15 blocks per hour due to the absence of PoS and increase from there on out.  This is initially a little slower than LTC, then about about the same rate.

Great! I like how you are taking gradual steps with the speed implementation. I also appreciate your preference for proof of work over proof of stake. Best to keep the tried and true technologies at the forefront.

I'm assuming the reason you are implementing a lot of things gradually is so that you have time to tinker with them before they come into full effect? That's a much better tactic than having to take a step backwards after you've realized you overshot the mark.

[tacotime]

I'm assuming the reason you are implementing a lot of things gradually is so that you have time to tinker with them before they come into full effect? That's a much better tactic than having to take a step backwards after you've realized you overshot the mark.

Yes.  The PoS system described should be difficulty to game and has an enforced reward below that of PoW, so PoW should always be the dominant source of coins.

One shortcoming with PoS as I described is that if someone buys 40% of all the coins and hoards them, they will be eligible to get a bunch of stake blocks all at the same time.  If they could spam them fast enough they might be able to fork the network briefly, but only for four minutes average at most (and if something weird is going on inside the chain of blocks, clients should reject them anyway).

I should probably add to the whitepaper that (1/129600) * total number of coins is the minimum number of coins required to grab a stake block, but that if you have multiples of that are all the same age you can grab a bunch consecutively if you so want to.  I assumed that the wallet would be implemented to do this automatically, but it may not have been clear from the whitepaper that this happened.

I guess you can also enforce throughout the network to only accept one stake block maximum every two minutes and reject the rest to help even out the distribution of stake blocks over time.

Edit: Yeah, I see a weakness now.  There should be some sort of measure to ensure a minimum time between PoS blocks of 1.5 or 2.0 minutes.  I don't think it'll be that hard to enforce -- just make the network reject the PoS blocks if the timestamp is too close to that of the previous timestamp.

[twelph]

I'm assuming the reason you are implementing a lot of things gradually is so that you have time to tinker with them before they come into full effect? That's a much better tactic than having to take a step backwards after you've realized you overshot the mark.

Yes.  The PoS system described should be difficulty to game and has an enforced reward below that of PoW, so PoW should always be the dominant source of coins.

One shortcoming with PoS as I described is that if someone buys 40% of all the coins and hoards them, they will be eligible to get a bunch of stake blocks all at the same time.  If they could spam them fast enough they might be able to fork the network briefly, but only for four minutes average at most (and if something weird is going on inside the chain of blocks, clients should reject them anyway).

I should probably add to the whitepaper that (1/129600) * total number of coins is the minimum number of coins required to grab a stake block, but that if you have multiples of that are all the same age you can grab a bunch consecutively if you so want to.  I assumed that the wallet would be implemented to do this automatically, but it may not have been clear from the whitepaper that this happened.

I guess you can also enforce throughout the network to only accept one stake block maximum every two minutes and reject the rest to help even out the distribution of stake blocks over time.

I was wondering when someone would come around and implement all of the cool features we are seeing in other alt-currencies at once, yet you seemed to have taken it another step further. How much of the code do you plan on borrowing directly from BTC using their stable base? Without trying to pick on an obvious influence for your current model, it's nice how your are already showing the inner working of the math involved within the original alpha white paper. Something that PPC is still lacking in my opinion.

[tacotime]

I was wondering when someone would come around and implement all of the cool features we are seeing in other alt-currencies at once, yet you seemed to have taken it another step further. How much of the feautures do you plan on borrowing directly from BTC using their stable code as a base? Without trying to pick on an obvious influence for your current model, it's nice how your are already showing the inner working of the math involved within the original alpha white paper. Something that PPC is still lacking in my opinion.

Thanks.  I think it's best to go over the theory really hard before even trying to put it into code.  I want to try to stick as closely to the original BTC code as possible.

If Sunny King or other PPC folks want to chime in, I'm kind of curious as to how PPC prevents brief forks using rapid bursts of stake blocks.  The network time method seems like the easiest and most foolproof method to implement, but I'm wondering if there's some kind of major problem with it.

[twelph]

I was wondering when someone would come around and implement all of the cool features we are seeing in other alt-currencies at once, yet you seemed to have taken it another step further. How much of the feautures do you plan on borrowing directly from BTC using their stable code as a base? Without trying to pick on an obvious influence for your current model, it's nice how your are already showing the inner working of the math involved within the original alpha white paper. Something that PPC is still lacking in my opinion.

Thanks.  I think it's best to go over the theory really hard before even trying to put it into code.  I want to try to stick as closely to the original BTC code as possible.

If Sunny King or other PPC folks want to chime in, I'm kind of curious as to how PPC prevents brief forks using rapid bursts of stake blocks.  The network time method seems like the easiest and most foolproof method to implement, but I'm wondering if there's some kind of major problem with it.

Last question. Is the name MC2 based off of E=MC²? Can't wait to point a rig at this, keep working hard!

[tacotime]

Last question. Is the name MC2 based off of E=MC²? Can't wait to point a rig at this, keep working hard!

It's double entendre of this and a reference to my first idea for a coin, Memcoin (which turned out to be a bad idea because you don't want to use high memory scrypt for a blockchain PoW hash).

[chriswen]

Going to read the whitepaper, another awesome legit alt currency hopefully (we haven't seen that many)

[master-P]

How would you prevent someone from messing around with the democratic voting system? Would they be able to game it using multiple clients/computers/VMs?

[BluesBrother]

Democracy per head or democracy per coin?
If democracy per head doesn't it loose the service of anonymity aspect?
Not that it is a huge problem considering it could take the whole thing out of the gray world into the white but it's still something to consider.


Thanks for posting this! It got me interested in PPC as well which seems to have a constant inflation rate according to you paper.
But one that is adjustable would perhaps be better.

[fcmatt]

How would you prevent someone from messing around with the democratic voting system? Would they be able to game it using multiple clients/computers/VMs?

There are ppl out there who have access to large blocks of ips. If i put my mind to it i can borrow /18 ranges of ips for a month or two. I have done it before and always have access to many /24s.

[chriswen]

Hmm, will a CPU miner be released when the coin is released?

[chriswen]

I'm assuming the reason you are implementing a lot of things gradually is so that you have time to tinker with them before they come into full effect? That's a much better tactic than having to take a step backwards after you've realized you overshot the mark.

Yes.  The PoS system described should be difficulty to game and has an enforced reward below that of PoW, so PoW should always be the dominant source of coins.

One shortcoming with PoS as I described is that if someone buys 40% of all the coins and hoards them, they will be eligible to get a bunch of stake blocks all at the same time.  If they could spam them fast enough they might be able to fork the network briefly, but only for four minutes average at most (and if something weird is going on inside the chain of blocks, clients should reject them anyway).

I should probably add to the whitepaper that (1/129600) * total number of coins is the minimum number of coins required to grab a stake block, but that if you have multiples of that are all the same age you can grab a bunch consecutively if you so want to.  I assumed that the wallet would be implemented to do this automatically, but it may not have been clear from the whitepaper that this happened.

I guess you can also enforce throughout the network to only accept one stake block maximum every two minutes and reject the rest to help even out the distribution of stake blocks over time.

Edit: Yeah, I see a weakness now.  There should be some sort of measure to ensure a minimum time between PoS blocks of 1.5 or 2.0 minutes.  I don't think it'll be that hard to enforce -- just make the network reject the PoS blocks if the timestamp is too close to that of the previous timestamp.

Are you sure you want to enforce it like that?

Because all other crypto-currencies don't have a hard limit.  Bitcoin blocks could be found 1-2 minutes away from each other and  that's allowed.  You should control stake blocks off of the difficulty it is too mine them.

It's based off of hashing right?  It's luck and the difficulty factor determines when the blocks are found.  Having Pow, PoS, one after another would be very unlikely.

[Joe_Bauers]

Democracy per head or democracy per coin?

Democracy per coin already has a (somewhat) proven real world method in voting shares for public corporations.  

[chriswen]

Democracy per head or democracy per coin?

Democracy per coin already has a (somewhat) proven real world method in voting shares for public corporations.  

Democracy is based on PoW blocks and PoS blocks.  So, hashing power and also, and stake power is used for votes (it's in the whitepaper).
Each block contains a vote.

Okay, for PoS.  So unlike PPC, your shares only gain value if you find a block.  (right?).  With PPC your coinstake accrues.

And the voting system sounds really cool.  But, we won't be able to see it implemented for 30 years.

[Impaler]

Can the draft doc be hosted somewhere else, this current 'mega' site is asking me to agree to terms-of-use and download flash just to download a simple file which is absurd.  Please use a host that dose not shaft people.