DagCoin: a cryptocurrency without blocks

[monsterer]

The transaction links point to related transactions, such as inputs and outputs in bitcoin, or completely unrelated?

[tromp]

The transaction links point to related transactions, such as inputs and outputs in bitcoin, or completely unrelated?

Outputs consumed by the tx are already linked to.

These are unrelated and should be recent tips of the DAG.

[monsterer]

Outputs consumed by the tx are already linked to.

These are unrelated and should be recent tips of the DAG.

You could imagine a DAG where the only connections between transactions are the inputs and outputs - the tips are the unspent outputs. I take it this design is not that?

[sickpig]

I was just thinking to myself, "but how will the initial distribution be handled under this coin?"... and then I suddenly realised the problem is already solved  .

This, or similar such ideas, sound like a potential solution to the possible problems when bitcoin hits the zero block reward stage. To be exploring that area so early is an optimistic sign  

no need of coin initial distribution in the case it is operated as a sidechain, right?

[Carlton Banks]

I was just thinking to myself, "but how will the initial distribution be handled under this coin?"... and then I suddenly realised the problem is already solved  .

This, or similar such ideas, sound like a potential solution to the possible problems when bitcoin hits the zero block reward stage. To be exploring that area so early is an optimistic sign  

no need of coin initial distribution in the case it is operated as a sidechain, right?

Well, I was thinking more about replacing the main chain with a chain like this: one that does not depend on 3rd party mining, i.e. directly peer to peer.

I think it's fair to say that it's still an open question as to whether the zero block reward situation can be sustained on fees alone. If differentiation of nodes from miners could be made redundant by a DAG chain design  (or some other tree type chain that enables the same), then why keep that? Such a change would obviously have an ideal decentralising effect on how the hashrate is distributed, it sounds like a big design win to me.

[Remember remember the 5th of November]

I think we're getting to a point where it's sort of a "Jack of all trades, Master of none" type of situation where more and more cryptos are churned out and not one is being solely focused on to further it.

[GingerAle]

I think we're getting to a point where it's sort of a "Jack of all trades, Master of none" type of situation where more and more cryptos are churned out and not one is being solely focused on to further it.

But all of the cryptos are furthering crypto. gmaxwell said it himself in that elements video - its become difficult (or near impossible) to experiment with the primary blockchain; hence, sidechains. And indeed, other cryptos test things beyond the primary technology - for instance, one interpretation of Monero's apparent staying power is that people have trusted cryptocurrency enough to not even need to see their transaction on the blockchain with their own eyes. I ponder what types of tangential aspects the DAG-type protocol would test.  

sorry for the off topic, those comments confuse me.

Interesting proposal - I thought I came up with something crazy yesterday and then was pointed to this post. My initial confound was the distribution, but as you mentioned, having this function as a sidechain is an interesting solution or just in general having it deployed on an extant blockchain.

IMO, one of the interesting aspects of this concept is that it furthers decentralization. Though one concern I haven't worked through is whether a nefarious actor could control the "blockchain" if they just continued to transact, being willing to part with some % of their money in fees in exchange. But these thoughts could be nascent... need to read more.

[Carlton Banks]

IMO, one of the interesting aspects of this concept is that it furthers decentralization. Though one concern I haven't worked through is whether a nefarious actor could control the "blockchain" if they just continued to transact, being willing to part with some % of their money in fees in exchange.

I think it could be done entirely without fees, just using valid proof of work as the means for verification.

Fees lose their structural role when the verification is done 100% p2p, because the incentive for the participants to donate proof of work is so that they can use their money the same as all others. And DAG fits the real world usage model; provide the proof of work when it is needed, i.e when the participant wishes to make a transaction. It almost sounds to good to be true though, so I share your cautious optimism, which is why it needs examining. The idea is deserving of it.

[P-Funk]

Really cool to know people are working on viable cryptocurrency beyond the Bitcoin model.  I have a suggestion for you if your vision is to see your creation become a successful proof of concept like Bitcoin is. Please choose a good name! DagCoin doesn't particularly stand out, or roll off the tongue well in my personal opinion.

[monsterer]

A key epiphany is that POW = coins. So you can replace transaction fees with solving a POW to send a transaction. The only real problem with that is the difficulty factor, difficulty must not be so high that sending a transaction is impossible on a home computer, but yet be high enough that the network doesn't start suffering sybil attack as bitcoin's is.

[Come-from-Beyond]

A key epiphany is that POW = coins. So you can replace transaction fees with solving a POW to send a transaction. The only real problem with that is the difficulty factor, difficulty must not be so high that sending a transaction is impossible on a home computer, but yet be high enough that the network doesn't start suffering sybil attack as bitcoin's is.

Or you could pay money to someone to find a PoW nonce for you.

[Carlton Banks]

I'm reminded of Tier Nolan's helical chains proposal. The idea there was to create a minimum of 4 main chains, as a way of decreasing the (average) block interval by the same factor. This had the secondary advantage that the mining market would experience a decentralising effect, as a lower practical block interval lowers the barriers to entry (finding blocks), but all without compromising the orphan rate. Possibly important to propagation in the world of >1MB blocks.

Be interesting if this could be applied to the main chain as a staged transition; sympathising with the block halving schedule, firstly introducing something like the helical chains idea, with the provision that the helical codebase could be then be ported to the pure p2p of a DAG style system as block reward hits zero.

[GingerAle]

IMO, one of the interesting aspects of this concept is that it furthers decentralization. Though one concern I haven't worked through is whether a nefarious actor could control the "blockchain" if they just continued to transact, being willing to part with some % of their money in fees in exchange.

I think it could be done entirely without fees, just using valid proof of work as the means for verification.

Fees lose their structural role when the verification is done 100% p2p, because the incentive for the participants to donate proof of work is so that they can use their money the same as all others. And DAG fits the real world usage model; provide the proof of work when it is needed, i.e when the participant wishes to make a transaction. It almost sounds to good to be true though, so I share your cautious optimism, which is why it needs examining. The idea is deserving of it.

Hrm - this means I haven't fully digested the research done in the OP. In my imagining of this, the verification is still "crowdsourced" and not directly p2p. I.e., when you make a transaction, you're also making a block candidate, with your transaction "on top". If you're POW fails to meet difficulty, your transaction/block candidate hybrid joins a pool of other failed block candidates. (or one can imagine a temporary failchain, but this might be similar to the DAG). Once a successful POW is obtained, that block candidate is accepted into the blockchain, and the other failed candidates are cleared (or if they are linked on a failchain, they naturally clear). In this version, you prevent spamming the work-space (like is currently done with bitcoin) by forcing every POW to include a novel transaction.

I know there are holes in the above. So I should go back to trying to understand this DAG thing.

But indeed, as you say, if you remove the fees (or the any blatant incentive for supporting the network), then there's no incentive to spam the workspace.

[Carlton Banks]

But indeed, as you say, if you remove the fees (or the any blatant incentive for supporting the network), then there's no incentive to spam the workspace.

Right, because you have to expend the work for every transaction, so it's not really free, you pay a non-monetary fee. So a cryptographic/work proof fee instead, not unlike the incentive aspect of the original hashcash.

[monsterer]

Or you could pay money to someone to find a PoW nonce for you.

Having a p2p market for hashes opens all kinds of doors

[GingerAle]

I ponder how full node maintenance is incentivized in this architecture, if at all.

[Sergio_Demian_Lerner]

I ponder how full node maintenance is incentivized in this architecture, if at all.

Same as in Bitcoin. Miners are no longer the full nodes maintainers. Only pools and users are.

To incentivize users mining on top of your transaction, you could add a fee to be taken by the confirmating tx. But to prevent orphaning wars, the maximum fee should be limited. DECOR+ is too expensive in terms of additional overhead to implement as per-transaction basis. And if tx fees are shared, txs would need to specify an additional payout address for accumulation of fees. That is not good for a txout-based ledger, because it generates too many spamming utxos. I can work for an account-based ledger. For example, if tx1 attach a fee of F, then the fist confirmation tx gets F*0.4, the next one gets F*0.3, next 0.2, last 0.1.

[americanpegasus]

I'm sorry that this topic is a little above my head.  I'm posting here mainly to monitor it in the future. 
 
That being said, my concerns is that this sounds a lot like the "torrent" based blockchain I was thinking about the other day.... not every node needs to carry the full blockchain; just portions of it.  That way anyone who wanted to verify the entire 7XB blockchain could do so (though laboriously) by assembling all the pieces of the "torrent". 
 
My only concern with a crypto with just nodes would be ELI5 solutions to the obvious problems like double-spending, Sybil attacks, accidentally incentivizing centralization, etc. 
 
The beautiful thing about Bitcoin (and Cryptonote) is that its possible to simplify them down to analogies that even a 'grandmother' can understand.  Let's hope this DAG-concept is capable of the same.

[JeWay]

I never even think that this thing exist, this is a brilliant idea!!!

[Come-from-Beyond]

I never even think that this thing exist, this is a brilliant idea!!!

This idea naturally follows from blockchain if you do few simple steps:

1. Get rid of the coinbase transaction
2. Allow only one transaction per block
3. Allow to reference several previous blocks at the arbitrary height

As all obvious things this didn't attract much attention, of course.