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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 proo

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.

SheinhardtWigCo 5y ago
I tried to read the whitepaper too. It's either total nonsense or I'm just not getting it. "Proof of History" appears to mean that trusted verifiers maintain the network.
- Zamicol 5y ago
  It's a subset of PoS. It's totally marketing. "Our PoS is so novel it deserves it's own name."
a1371 5y ago
PoH is essentially just PoW: more blocks mean more time has spent. I don't know why they just named it something different. Since SOL is not really decentralized, the validators can communicate a lot faster. So that's the difference with a usual blockchain where the latency is higher.
- mattdesl 5y ago
  It appears quite different than PoW, which is how it is able to boast so much higher throughput. https://tokens-economy.gitbook.io/consensus/chain-based-proof-of-capacity-space/proof-of-history https://tokens-economy.gitbook.io/consensus/chain-based-proo... https://medium.com/solana-labs/proof-of-history-explained-by-a-water-clock-e682183417b8 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.
  - keymone 5y ago
    PoW has nothing to do with throughput.
    - mattdesl 5y ago
      In theory no; but in practice yes. PoW relies on miners competing for the next block, and block size/time tends to always be a bottleneck for scalability. This is why most secure PoW blockchains have a very low throughput. 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.
      - keymone 5y ago
        PoW, PoS, PoWhatever in context of blockchains are all consensus reaching protocols. An input to consensus reaching protocol in blockchains is a block hash. Consensus reaching protocol doesn't care if that hash represents 1 transaction or 1 trillion transactions, therefore throughput doesn't depend on which consensus reaching mechanism you pick. 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.
wqsz7xn 5y ago
It's marketing mostly. A lot blockchainers rehash well known concepts to front innovation.
opheliate 5y ago
I’m very confused by why PoH is being presented as novel, maybe I’m misunderstanding? As I see it, PoW and PoH both appear to be solving the same problem of establishing a sequential order of events within a distributed system, except PoH doesn’t present a mechanism for trusting the sequence. 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.
- deleted 5y ago
  [deleted]
- TimJRobinson 5y ago
  As far as I can tell PoH is done by hashing the same value over and over (where each hash is hashing the last hash), to prove you've done some amount of work on that block. So blocks contain both the hash of the previous block and a PoH hash which is showing you've iterated SHA256 n times. This way you can't spam the network with blocks. It seems similar to how NANO works. I still don't know why it's called proof of history.
remolacha 5y ago
Sybil control mechanisms like PoW, PoS, and PoH are intended to rate-limit block producers, in order to prevent any one entity from controlling the network. In Bitcoin PoW, a block is produced every 10 mins, and your chance of getting to propose the next block is related to your hash power. All block producers are competing for the same slot in the blockchain. 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.
- SheinhardtWigCo 5y ago
  > This is actually a novel Sybil control mechanism that is more efficient than standard PoW/PoS. 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?
  - nivertech 5y ago
    No, PoW can be parallelized, but VDF/PoET cannot, that's why it's also called PoSW. PoW (Proofs of Work) PoSW (Proofs of Sequential Work) VDF (Verifiable Delay Function) PoET (Proof of Elapsed Time)
    - keymone 5y ago
      Why can’t it be parallelized?
EMM_386 5y ago
I found some more information on PoH here: https://lsmod.medium.com/what-makes-solana-the-fastest-public-blockchain-cb8ffde1a7f4 https://lsmod.medium.com/what-makes-solana-the-fastest-publi...

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.

SheinhardtWigCo 5y ago

I tried to read the whitepaper too. It's either total nonsense or I'm just not getting it. "Proof of History" appears to mean that trusted verifiers maintain the network.

Zamicol 5y ago
It's a subset of PoS. It's totally marketing. "Our PoS is so novel it deserves it's own name."

a1371 5y ago

PoH is essentially just PoW: more blocks mean more time has spent. I don't know why they just named it something different. Since SOL is not really decentralized, the validators can communicate a lot faster. So that's the difference with a usual blockchain where the latency is higher.

mattdesl 5y ago
It appears quite different than PoW, which is how it is able to boast so much higher throughput. https://tokens-economy.gitbook.io/consensus/chain-based-proof-of-capacity-space/proof-of-history https://tokens-economy.gitbook.io/consensus/chain-based-proo... https://medium.com/solana-labs/proof-of-history-explained-by-a-water-clock-e682183417b8 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.
- keymone 5y ago
  PoW has nothing to do with throughput.
  - mattdesl 5y ago
    In theory no; but in practice yes. PoW relies on miners competing for the next block, and block size/time tends to always be a bottleneck for scalability. This is why most secure PoW blockchains have a very low throughput. 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.
    - keymone 5y ago
      PoW, PoS, PoWhatever in context of blockchains are all consensus reaching protocols. An input to consensus reaching protocol in blockchains is a block hash. Consensus reaching protocol doesn't care if that hash represents 1 transaction or 1 trillion transactions, therefore throughput doesn't depend on which consensus reaching mechanism you pick. 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.

wqsz7xn 5y ago

It's marketing mostly. A lot blockchainers rehash well known concepts to front innovation.

opheliate 5y ago

I’m very confused by why PoH is being presented as novel, maybe I’m misunderstanding? As I see it, PoW and PoH both appear to be solving the same problem of establishing a sequential order of events within a distributed system, except PoH doesn’t present a mechanism for trusting the sequence. 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.

deleted 5y ago
[deleted]
TimJRobinson 5y ago
As far as I can tell PoH is done by hashing the same value over and over (where each hash is hashing the last hash), to prove you've done some amount of work on that block. So blocks contain both the hash of the previous block and a PoH hash which is showing you've iterated SHA256 n times. This way you can't spam the network with blocks. It seems similar to how NANO works. I still don't know why it's called proof of history.

remolacha 5y ago

Sybil control mechanisms like PoW, PoS, and PoH are intended to rate-limit block producers, in order to prevent any one entity from controlling the network. In Bitcoin PoW, a block is produced every 10 mins, and your chance of getting to propose the next block is related to your hash power. All block producers are competing for the same slot in the blockchain. 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.

SheinhardtWigCo 5y ago
> This is actually a novel Sybil control mechanism that is more efficient than standard PoW/PoS. 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?
- nivertech 5y ago
  No, PoW can be parallelized, but VDF/PoET cannot, that's why it's also called PoSW. PoW (Proofs of Work) PoSW (Proofs of Sequential Work) VDF (Verifiable Delay Function) PoET (Proof of Elapsed Time)
  - keymone 5y ago
    Why can’t it be parallelized?

EMM_386 5y ago

I found some more information on PoH here: https://lsmod.medium.com/what-makes-solana-the-fastest-public-blockchain-cb8ffde1a7f4 https://lsmod.medium.com/what-makes-solana-the-fastest-publi...