Forget using POW to secure a ledger. It's comically bad because of the wasteful arms race which now makes each transaction take as much energy as a household does in a day(!)
The reason bitcoin is so far ahead is because it was the first. Proof of work to secure the blockchain AND also elect a dictator to mine the next block is cute, but I wish they had decoupled it, as they did for example for bitcoin-ng.
What I am far, far more interested in is proof of work for avoiding sybil attacks, or used COLLABORATIVELY by nodes to secure a history, as done in Ripple for example.
So, back to sybil attacks: proof of work, can we trust it?
What are the best ways to make it expensive for an attacker to create multiple identities, yet cheap for everyone else to make one identity?
One is the cumulative time and activity invested by you and those who invited you.
For example, reputation. Maybe making accounts is cheap but reputation comes from random nodes with reputation upvoting you. But then you can spam all those nodes since they're operated by humans.
It seems we have yet to design a system that's truly impervious to sybil attacks. The best we have is tying things to a human real world transaction, eg buying a smart phone, and hoping that whoever made the smart phone also has a service to sign data (they don't) that wasn't compromised.
Any other ideas? Paying for accounts with bitcoins? That at its root is just back to the proof of work arms race and reputation of bitcoin.
Question: is there some sort of service by the Secure Enclave that can sign a piece of data with an HMAC or something to prove that it was signed on a legitimate, non-jailbroken smart device?
Secure distributed ledger, without PoW, without PoS.
The bad side? Not 100% trust-less like blockchains, instead (number chosen by no real reason) only has to trust that majority of 12 witnesses does not collude. The witnesses should have real world identities.
Basically transforming what bitcoin has become, with few mining pools/operators deciding its fate and whom users anyway have to trust - into witnesses which can be replaced.
> Basically transforming what bitcoin has become, with few mining pools/operators deciding its fate and whom users anyway have to trust - into witnesses which can be replaced.
This is a poor analogy because colluding Bitcoin miners can never steal funds; they just stamp a chain with proof of work, while the Bitcoin P2P network verifies the stamped blocks, and rejects them if they’re invalid. In the case of Byteball, colluding witnesses can steal funds, which becomes increasingly problematic as the value of the currency increases.
With Ripple, no one can steal money. Just like with bitcoin, all transactions have to be signed by the payer at least. However, instead of POW being what selects the next miner, there's a different consensus algorithm that doesn't waste electricity. And Ripple moves more money than bitcoin per day.
I don’t dispute that. Ripple is centralized, there are dozens of centralized payment systems out there, but that’s not what Bitcoin is competing against. Creating performant, centralized payment systems are a solved problem. The question is what Ripple brings to the table that the other payment systems don’t.
Bitcoin is just as centralized now in practice. There are just a few mining pools that have the most electricity to spend. In Ripple they will eventually expand the number of main nodes way beyond what bitcoin has.
Once a transaction has been made you just need SOMEONE to confirm it for the blockchain. In bitcoin, that's the miner that happened to solve the POW. If they don't take your transaction, the next miner will. In Ripple it's effectively the same thing.
Even with Byteball the witnesses cant steal funds or generate new ones without the other full nodes noticing and rejecting the same way as other bitcoin full nodes can reject if a miner generates a 10000 coinbase reward to itself.
I don’t understand. If nodes do not accept whatever the witnesses say is the true transaction history, why are the witnesses needed in the first place?
I know that it’s not possible for a witness to fake some users signature, and send these funds to themselves, but that’s not the attack we need to worry about. The attack we need to worry about is witnesses colluding to present a false history of transactions, such that the user’s funds (that the miners want) were never sent to that user in the first place, thus remaining the property of the coinbase owner. Since all coins originate as a coinbase, if witnesses go far enough back in time, all coins are theirs.
The reason bitcoin is so far ahead is because it was the first. Proof of work to secure the blockchain AND also elect a dictator to mine the next block is cute, but I wish they had decoupled it, as they did for example for bitcoin-ng.
What I am far, far more interested in is proof of work for avoiding sybil attacks, or used COLLABORATIVELY by nodes to secure a history, as done in Ripple for example.
So, back to sybil attacks: proof of work, can we trust it?
What are the best ways to make it expensive for an attacker to create multiple identities, yet cheap for everyone else to make one identity?
One is the cumulative time and activity invested by you and those who invited you.
For example, reputation. Maybe making accounts is cheap but reputation comes from random nodes with reputation upvoting you. But then you can spam all those nodes since they're operated by humans.
It seems we have yet to design a system that's truly impervious to sybil attacks. The best we have is tying things to a human real world transaction, eg buying a smart phone, and hoping that whoever made the smart phone also has a service to sign data (they don't) that wasn't compromised.
Any other ideas? Paying for accounts with bitcoins? That at its root is just back to the proof of work arms race and reputation of bitcoin.
Question: is there some sort of service by the Secure Enclave that can sign a piece of data with an HMAC or something to prove that it was signed on a legitimate, non-jailbroken smart device?