Proof-of-History (PoH)


Proof of History (PoH) nodes have internal clocks that validate events and time. The incoming events are hashed using a verifiable delay function, also known as VDF.

What Is Proof-of-History (PoH)?

Deployed by Solana, Proof of History (PoH) is a method of incorporating time itself into the blockchain, attempting to reduce the load on network nodes while processing blocks. In a traditional blockchain, gaining consensus on the time a block was mined is just as important as getting consensus on the transactions in that block. Because timestamping informs the network (and any observer) that transactions occurred in a specific order, it is crucial.
The successful block miner in a Proof of Work (PoW) scenario is the first to determine the proper nonce, which takes a given amount of computer power. Proof of History (PoH), on the other hand, employs Verifiable Delay Functions (VDFs). Only a single CPU core can solve a VDF by performing a certain set of consecutive steps. Because no parallel processing is permitted, it is simple to determine how long each step will take. 

Proof of History (PoH) overcomes the time barrier, making blockchain lighter and quicker by reducing the processing weight. Solana combines Proof of History (PoH) with Tower Byzantine Fault Tolerance (Tower BFT), a security system that allows users to stake tokens to vote on the validity of a PoH hash. 


Low Fee: Solana offers cheaper transaction fees in comparison to other networks, such as Ethereum. As a consequence, Solana is an excellent choice for frequent transactions and money transfers.

Scalability: Transactions on the Solana network are quick. As a result, the whole picture gains scalability.


Solana presently employs less than 1,200 validators to validate transactions on its network.
Solana is sometimes referred to as an Ethereum killer however there are fewer dApps on the network in comparison. On Solana, around 350 dApps have been developed, but on Ethereum, over 3,000 dApps have been built.

Proof of History (PoH) vs Proof of Stake (PoS)

Proof of Stake and Proof of History are quite similar. This is due to the fact that Proof of Stake evolved into Proof of History. Both algorithms are built on the same foundation. Validators are used in both algorithms to guarantee that transactions are validated and new blocks are created.

However, there is a significant difference between these two methods in terms of how time is calculated. The timestamp function is used in Proof of Stake. This means that each node relies on the network's timestamp. Because time must flow via the network first, the network will operate slower.

This isn't essential with Proof of History since it employs the Verifiable Delay Function, which calculates the time based on historical occurrences. After analyzing these occurrences, a hash function is constructed that can be confirmed by anybody. Every block created by the network has this hash appended to it. This method of determining the time takes essentially little time, making the Solana blockchain incredibly scalable at the moment.

Potential Issues with Proof of History (PoH)

Proof of History is a consensus mechanism based on Proof of Stake, but with a different method of calculating time. Historical events are now used to determine the passage of time. These events are transformed into a hash, which can only be generated by previous events. The hash cannot be forged in any way.

Solana is the only blockchain that employs the Proof of History algorithm. Therefore, the blockchain is incredibly scalable, capable of processing up to 60,000 transactions per second. PoH guarantees that determining the timing of a transaction takes less time.

Proof of History, on the other hand, has a number of flaws. For example, this method has never been put to the test on a wide scale, so we don't know if it actually works flawlessly. Furthermore, various vulnerabilities and attacks in Solana have been discovered in the past, some of which were caused in part by Proof of History. As a result, we're not sure if Proof of History is a safe consensus mechanism yet.