Can someone explain what is proof of history? I tried to read the white paper but don't understand what PoH is supposed to achieve or how it interacts with proof of stake.
As I understand PoH, blocks are instead continually proposed, but block producers are rate-limited by having to show completion of an operation similar to a verifiable delay function. Therefore, block producers avoid having to all compete for the same slot in the blockchain and duplicate lots of work. This is actually a novel Sybil control mechanism that is more efficient than standard PoW/PoS. It's somewhat analogous to the difference between a dedicated communication channel (as in landline phones) and a packet-switched communication channel (as in the internet).
The catch is that the PoH operation approximates a verifiable delay function, but is not currently proven to be equivalent to one. So there's the possibility of a black swan event where someone discovers a clever way to speed up the PoH operation, allowing them to cheaply control the network. Another knock against Solana is that although it has innovated in transaction efficiency, its token distribution/crypto-economics may be less "fair" than competitor blockchains. Please correct me if you spot any mistakes.
It's not novel, it's PoW with a different name. The "verifiable delay function" is hashing, which you can speed up by using faster GPUs or ASICs. Doesn't that sound familiar?
PoW (Proofs of Work)
PoSW (Proofs of Sequential Work)
VDF (Verifiable Delay Function)
PoET (Proof of Elapsed Time)PoET (Proof of Elapsed Time) works differently, there you basically running a sleep or a timer inside an Intel SGX secure enclave, so you have to trust Intel, and also need to hope that there are no security vulnerabilities there.
When used for leader selection, VDF’s offer a substantial improvement over verifiable random functions. Instead of requiring a non-colluding honest majority, VDF-based leader selection only requires the presence of any honest participant. This added robustness is due to the fact that no amount of parallelism will speed up the VDF, and any non-malicious actor can easily verify anyone else’s claimed VDF output is accurate. [1]
[1] https://blog.trailofbits.com/2018/10/12/introduction-to-veri...
how is that different from one miner finding a valid signature faster than the other?
and how is that not parallelization?
Bitcoin miners can parallelize because it's a search problem, so they can probe multiple different candidates simultaneously.
That said, VDF isn't a drop in replacement for Bitcoin style POW. VDF just gives you the ability to say (provably, so no one can cheat) "everyone has to do a 10 minute serialized computation before launching a (parallelizable) POW hash search" so we don't use all the world's available electricity just for mining.
Except it’s going to be worse because VDF is the centralizing factor, it’s like having bitcoin where constructing a block takes really long time. The actor that finishes first has the advantage to start PoW and will win disproportionate amount of blocks by revealing their data at the last possible moment, preferably when or just before another actor publishes their “worse” PoW.
PoSW is a subset of PoW. To say "PoW can be parallelized" isn't necessarily true.
In PoW, each event that is to be published must be accompanied by the hash of the previous event in the sequence. In PoH, the same is true. In PoW, you trust that the chain of events is correct, because work has to be put in to generate each hash, as there are conditions on the digest prefix which determine the difficulty. With PoH… Um… I’m sure I must have missed something, but there’s no inherent reason to trust any chain. It’s just a sequence of hashes, with no difficulty requirement. The actual trust in a certain chain comes from an unrelated proof of stake system, I guess. Very weird, I’d appreciate if anyone could help me get some clarity on this.
It seems similar to how NANO works. I still don't know why it's called proof of history.
It's totally marketing. "Our PoS is so novel it deserves it's own name."
https://tokens-economy.gitbook.io/consensus/chain-based-proo...
https://medium.com/solana-labs/proof-of-history-explained-by...
I agree it doesn’t seem very decentralized at the moment (not many validators and most support coming from the foundation) but that may change if the platform is able to scale.
Solana’s approach to PoS + PoH + optimistic confirmation allows it to scale to an order of magnitude higher throughput than typical PoW blockchains while - they claim - retaining a degree of security & decentralization superior to a PoW mechanism were it to be scaled to the same network throughput (via block size/time adjustments). This is what makes it novel - if their marketing & whitepaper is to be believed.
Obviously, Solana’s throughput is achieved at the expense of security & decentralization compared to say ETH, but I suspect a PoW blockchain with nodes tuned to support 50K tps would not work at all.
so neither in theory nor practice, PoW has nothing to do with throughput, it's all just scammy marketing to sell you shitcoins. And in this case - extremely centralized, extremely censorable, extremely shady shitcoin.
https://lsmod.medium.com/what-makes-solana-the-fastest-publi...