Blockchain’s uses have gone beyond cryptocurrencies and laid the groundwork for new software applications. As the number of decentralised apps on blockchain networks continues to grow, transaction throughput performance is an important part of research and development. The Proof of History algorithm, or POH, has become one of the most popular ways to improve the speed of transactions.

Proof of History, which is a Verifiable Delay Function, has been added to the Solana blockchain as a way to add the idea of time to blockchain networks. Proof of History was made creatively that showed new ways to speed up transactions and how it could work with other consensus algorithms. The next post gives an overview of Proof of History and talks about how it fits into the blockchain ecosystem.

Solana

Solana is a layer 1 blockchain network. Developers could build layer 2 networks on top of it. Bitcoin and Ethereum are both types of layer 1 networks. Why is talking about Solana in a Proof of History talk important? The Proof of History consensus and Proof of Stake consensus methods were added to the Solana blockchain. Solana blockchain is a lot like Ethereum in many ways, like the fact that it has a native token called Sol.

Solana also has a distributed machine for running smart contracts and letting dApps and the blockchain talk to each other. Solana has also become a strong competitor to Ethereum by coming up with new and interesting ideas for its blockchain architecture. Proof of History blockchains like Solana are important to learn about because they offer a complete environment for building on-chain applications. Solana, for example, made more than 5000 NFT protocols available in 2022.

What Does “Proof of History” Mean?

Solana’s features make people wonder “what is Proof of History” and how it is different from other ways to reach a consensus. Consensus algorithms are one of the most important parts of blockchain networks, and they make each blockchain unique. Proof of History is a new feature of the Solana blockchain that can help lower transaction costs and make sure that transactions are processed faster. The consensus mechanism provides a way to prove the order of transactions and identify the events in each order using cryptography.

Proof of History can be used with consensus mechanisms like Proof of Stake and Work. In fact, the POH consensus is what makes Proof of Stake on Solana more reliable and efficient. Proof of History also makes sure that blockchain protocols have good decentralised security.

The most prominent innovation in #Solana is “Proof of History.” This is POH made simple. All the examples are taken from Solana white-paper/website.

A thread 🧵

— Naman (@namanmanchanda2) January 16, 2022

How Proof of History in the Works

When people ask, “How does Proof of History work?” the answers would point out the main goal of the consensus mechanism. As communication speed sped up a lot, the idea of standard time became a must. For example, computers and smartphones would check their internal clocks with a central clock before connecting to the internet to ensure accuracy. How can you talk about time in decentralised systems like blockchain networks where there is no central clock? When it comes to distributed systems, the problem of time is very important.

Blockchain networks could process transactions more quickly by timing the transactions in small chunks. Why would you need a Proof of History algorithm if you already have these kinds of answers? Most programmable blockchains like Ethereum get their median timestamps from programmes outside the blockchain.

The median timestamps help verify that transactions were made on the blockchain network in the exact order in which they were recorded. But using median timestamps from a centralised source goes against the ideas behind decentralised systems. Proof of History fixes the issue by letting timestamps be added directly to the blockchain network. The Verifiable Delay Function, or VDF, is the most important part of POH consensus.

Also, read – Top 5 Questions Answered About Proof Of Work

Verifiable Function Delay

The VDF, or Verifiable Delay Function, is an important part of Proof of History guides for beginners. Block producers have to go through the VDF to get to the production slot they want. Solana puts the VDF into action by adding data to the transaction sequence in a different way. Solana blockchains add the hash of information about states that have already been generated to the transaction sequence. The process makes it possible to publish the transaction’s input data, count, and state without being able to recreate the data or make other versions.

The use of data helps set a maximum time limit, and the ability of Proof of History to look up previous hashes lets time limits be set lower. In “how does Proof of History work,” one of the most important things to say about VDF is that it doesn’t give a precise time estimate for transactions that happen in a certain order. On the other hand, it can show exactly when an important global state machine event happened in the past or will happen in the future.

Block producers can use SHA256 hash functions to set up the VDF locally. The hash function allows almost real-time integration of VDF functions and is a major standard for most chip manufacturers. When looking at a blockchain, being able to keep track of time could help figure out when certain things happened.

Getting to know how Proof of History works

Proof of History is simple and easy to understand in terms of how it works. But the technical jargon could make it hard for people who are just starting out to understand the idea. A Proof of History blockchain uses timestamps to show when a block was added to the chain.

For example, if someone went to the Olympics and took a picture of a competition, they could prove that the picture was taken at the Olympics. It shows that the picture was taken during a certain time period. In simple terms, Proof of History helps make a record of past transactions that show that a certain event happened at a certain time.

The SHA256 hash function is a key part of answering the question “How do you implement Proof of History?” and explaining what it is. All of the events and transactions on the Solana blockchain are hashed with the SHA256 hash function. The function takes in information and gives back something unique and unpredictable. Then, Solana takes the output of the transaction and uses it as input for the next hash.

Cryptographic Hash Functions are an essential building block for #Blockchains.

SHA256 is the hash function used in #Bitcoin.
Keccak256 is the hash function used in #Ethereum.

1/ pic.twitter.com/y10zguagL0

— Infochain (@Infochain__) April 6, 2022

Now, the order of the transactions is added to the output that has been hashed. The process of hashing helps make a long, smooth chain of transactions that have been hashed. So, validators can add to a block a sequence of transactions that can be checked and is clear. Validators could check how much time has passed in the hashing process without having to use a traditional timestamp.

How does proof from history support the idea that things will be the same in the future?

Proof of History is a kind of secret timepiece. It works by giving each transaction a timestamp and a hash that shows when the transaction was verified. So, the whole blockchain network could stop focusing on making sure that transaction claims are checked in order. Proof of History, on the other hand, puts the spotlight on reconciling the global state of the blockchain as it is now.

The powerful mechanism for ensuring eventual consistency is a key part of the Proof of History algorithm’s ability to allow for fault tolerance in the network. The guarantee of eventual consistency protects against changes that have never been seen before because of large network partitions. Nodes would enforce the order of transactions based on how the system is set up or how it is running. So, the nodes could share more resources for processing blocks quickly and adding validated blocks to the distributed ledger.

Solana also uses the Proof of History consensus mechanism to protect against problems with fault tolerance in Byzantine systems. The new consensus method gets rid of the problems that come up when people in a group do something bad.

The Example of the Railroad

In the introduction to the Proof of History algorithm, the Solana blockchain’s railroad analogy is another interesting point. The railroad is used as an example or analogy for Proof of History to show how knowing the exact time of transactions makes it easier to check information. In the example, a person sends an important letter on a train that leaves New York at 9 am and arrives in Chicago at 5 pm. The train would make stops in Philadelphia, Pittsburgh, and Cleveland along the way. Because the letter is important, the person sending it must check the identity of the train at every stop.

In other blockchains, you would need a lot of time and money to figure out whether the information was correct at each step. For example, the station worker at the last stop must check with his colleagues at the other stops to make sure that the letter is on the train. Since there is no mark on the letter, the train is the only way to make sure it gets where it needs to go. Referring to a centralised schedule can slow down the whole process if it contains incorrect information.

The fact that the answer to “How do you implement Proof of History?” in the Solana blockchain shows how well it solves the railroad problem shows how well it works. With the Solana blockchain, the letter would get a stamp at each stop along with information about when it would arrive. The letter would have stamps from New York, Philadelphia, and Pittsburgh when it got to Cleveland. The station worker at Cleveland could put a stamp on the letter without asking anyone else at the station. As you can see, the Solana blockchain could save a lot of money and time by using Proof of History.

How does Solana combine Proof of History and Proof of Stake?

Proof of Stake is the right choice for the Solana blockchain, which needs a different way to reach a consensus than Proof of History. However, in Solana Proof of Stake, the validators check the transactions for blocks signed by Verifiable Delay Function. The VDF takes inputs and makes outputs that are hard to predict without actually running the function. In the lower block validation times, you can see how Solana combines Proof of History consensus with Proof of Stake.

Bottom Line

The clear idea of what Proof of History can do comes from its work and its detailed explanation of what it is. It is a new way to reach a consensus that could change how layer 1 blockchain networks are measured for performance. As the number of blockchain-based applications grows, networks need to offer faster throughput performance so that verification doesn’t take too long. The Proof of History feature on the Solana blockchain has made it easy to make blockchain transactions happen faster and for less money.

It helps prove the exact time when a transaction happened based on how the blockchain network is set up. The Verifiable Delay Function is used by the Solana blockchain to make the best use of time in blockchain networks. Proof of History is based on a theory of concepts that has real advantages for adding new uses to the blockchain system.