It cannot work on it's own as there is nothing at stake, allowing an attacker with large holdings in the future to rewrite the chain at no cost.

However, it can work in a hybrid model, where the sole purpose of POS is to solve the 51% hashpower attack problem. For more info, see Interleaved Mining,
https://bitcointalk.org/index.php?topic=1317240.0

The primary benefit of this approach is to not punish miners who are not hostile. It allows them to retain their investment in SHA256 hashing hardware.

I think you are greatly overestimating miner importance.

If all of Bitcoin's miners started mining Dogecoin tomorrow, would that make Dogecoin the new Bitcoin?

Just set minrelaytxfee to 0.0001 and you will have a much smaller and stable mempool.

The default setting allows spam to be accepted into the mempool and sticks around forever because those transactions will never be mined.

The goal is not to replace miners, that would be a violation of the social contract the protocol offered to miners.
Miners have invested large sums of money into protecting Bitcoin and screwing them is just not logical.

Also, as long as the current ASIC mining farms are protecting the chain, they are a great advantage as they greatly increase the barrier to attack the chain. The goal of the proposal is to leave revenue with them but diffuse political power by sharing it with stake holders. Or in other words, to increase diversity in miners so that 2-3 parties cannot hold the currency hostage.

The issue with such a scheme is that you add yet another magic number into the protocol, potentially causing rifts as to what the right amount should be.

Also as the bitcoin economy grows, we should expect wealth concentration to continue to dilute over to a larger number of people. Many small holders would not be willing to spend resources to run a node if the probability of mining a block is miniscule. So i would expect the number of coins being staked to decrease as Bitcoin grows, kind of the opposite effect you are looking for.

Also, number of coins staked != number of different ppl mining

Yup, sounds like you fully understand the advantages and how it would work.

Please read the first post for details, but in short there are few big goals

- Increase decentralisation of validation by incentivising full nodes
- Solve block propagation issues  by having smaller alternate blocks, allowing POW larger blocks without mining centralisation risk
- Prevent 51% POW mining attack

I highly doubt that will sit well with miners today.
I suppose the way the protocol would work is that 50% of the reward will be locked up, to be awarded 3 blocks later to whoever stamps the block.

Some downsides i see are:
- POS miners will lose the chance to mine transactions, which would have introduced much greater diversity in transaction selection (Increase censorship resistance)
- Block propagation advantage would be lost.

Upside is that POW hashrate is not reduced due to idle time.


That is perhaps the most important goal of this scheme.
Hardening the blockchain would significantly increase the security of the blockchain and in turn greatly increase viability of Bitcoin being a long term Store of Value.

AFAIK getutxo is not supported by Core as it is insecure to rely on the data.

The command is supported by XT.

I like the idea because it will prevent POW from going idle in between blocks.

But how would you stamp a POW block which has already been mined?
Does POS mine txns in the stamping scheme?
This also removes the block propagation advantages of interleaving.

Like i said earlier, the current intention is that generating a block would consume the age of the output used to generate the block, so your age is reduced to 0.

But even if the age was not consumed, i don't follow how that would be a problem?
If i was a POW miner with 20% hashrate, i would constantly have a 20% chance to generate a block, no?


No, rewards stay with POW miners.

It's simple really, if you don't mine a POS block, someone else will when the timestamp increments and their output gets lucky.

Yeah it was set at slowest, which says will confirm in 25 blocks, which is about 4 hours 

In future, you could drag it to the right if you need the payment done urgent.

Another good place to check is https://tradeblock.com/bitcoin/
Look at the right for Fee/size to see what the market is currently paying, pay slightly more for faster confirmation or less if you can wait.

This is not true as long as you can link 2 POW blocks together.

Eg:
POW 99 ==> POS 100 ==> POW 101

Even if i came up with a new POS 100A block later, i will need to perform more work than POW101 to attack the chain.

ie:

POW 99 ==> POS 100 ==> POW 101
             ||
            ==> POS100A ==> POW 101A

But if POS100 was already broadcast first, POW miners are not going to sit around to build atop POS100A when they see it later.

This is no different than a POW block race where miners build atop the first block they see.
Ask yourself, Why don't they switch?
Because if i own any hashpower < 50%, by mining atop the later block, i sabotage myself by increasing the chance that my block will be orphaned as the rest of the network is likely to be mining atop the earlier block instead.



This is no different than saying that a large Chinese mining pool can withold blocks and slow the network to a crawl.
This is actually far more dangerous with POW because the largest pools have over 20% of hashing power and 66% of hashing power is within China.
If the Chinese gov shutdown all pools in China, blocks would slow to 30 minutes.

Contrast that to BTC distribution where the largest holder has less than 5% stake.

See above reply. POW Miners will still build atop the first POS block they encounter as they have a real cost to mine ontop of a later block.

And you had it set to fastest setting?

So i think you are looking at it from the micro view, where the concern is regarding double spending during the POS block. That is a valid concern.

But firstly, it is incorrect to say that the whole chain becomes as insecure as POS.
Rather, if you think about it, the combination actually makes the chain far more secure than POW alone.
It basically makes it impossible for a 51% miner to take over the chain unless he also happens to have 50% of all BTC.

Regarding the double spending during POS blocks. POS basically works in the following form:

sha256(output hash + timestamp) = HASH
ValidProof(HASH) ~= Coin age * number of coins

So as far as POS is concerned, either you have a valid block or you don't. There is nothing further you can do about it.
Grinding is not possible for the current block.

Well, txns also have implications on the state of UTXO set and affect validity of future txns as well, so it isn't really different in practice.

What wallet are you using? Seems as if the auto fee function could use some tuning.

This is incorrect for several reasons.

1) The scenario you described is only valid for the POS block being currently mined, however this is no different than POW miners attempting to mine blocks and come up with 2 blocks around the same time. The network will eventually go with one fork and the other will be orphaned. In this case, it is the POW miners who decide which POS block is built atop.

2) Yes, you are right that pure POS is insecure because of the grinding problem which pretty much every POS coin tries to resolve via checkpointing by trusted parties.
In Interleaved mining, the checkpointing is instead done by POW miners based on whoever mines the next POW block just as the correct chain history is decided by POW today, POW will decide which POS block is the preceeding block.

To simplify this, think of POS blocks no different than ordinary Bitcoin txns, POW miners decide which is valid and in what order.

3) While i have not described the POS algo in detail yet (wish to get the high level idea across first), my current thinking wrt the "strength" of a POS block would be a combination of coins * age where inclusion of a POS block will consume coin age, thereby greatly reducing the probability that the same party will mine another POS block in the near future.

If you look at the blocks before your txn was included:

HeightTimeMinerElapsed# tx% new (?)Block ValueTotal FeesSizeFee/size (?)
392,1501h 15m ago - 07-Jan 20:05F2Pool12m 22s247651%14,513.683964990.40601258999,999 B40.6012986
392,1491h 27m ago - 07-Jan 19:53BTCChina31m 45s227797%22,482.465414900.56340120949,030 B59.3660
392,1481h 59m ago - 07-Jan 19:21Slush11m 58s168178%29,171.164376750.29257031749,158 B39.0532184
392,1472h 11m ago - 07-Jan 19:09AntPool14m 06s178390%16,789.758356120.36324329933,337 B38.91877
392,1462h 25m ago - 07-Jan 18:55AntPool2m 14s18954%12,945.036017510.25293064931,463 B27.1541263
392,1452h 27m ago - 07-Jan 18:52F2Pool23m 38s308377%26,494.591148470.61388991999,961 B61.3913852

It was basically a case of bad luck in that blocks were being found slower than 10 minutes, causing a backlog.
If you look at the last portion (BXXXXX), your fees/byte were lower than all the others that got included, so miners picked more urgent transactions instead of yours.

That is actually an interesting idea. The downside would be that it would effectively be a blocksize decrease as older nodes won't see POS blocks, only to see the relevant txns 20min later in the next POW block.

My personal opinion on the softfork idea is that if we are going increase blocksize sometime in the future, we would need a hardfork anyway. Increasing the blocksize has centralising effects and implementing this proposal together would do much to counteract and even improve decentralisation considerably.


Yes, this has been brought up, although id like to hear from a miner why this might be an issue if all miners are affected equally by this.

RBF is opt-in, so it is not forced on anyone.
You are free to not use it if you don't want to.
It just offers an additional option for those who need it.

So i really don't see what all the fuss is about.