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How to Build a Proof of Existence Blockchain with Substrate?


Blockchain is defined as a decentralized ecosystem driven by distributed ledgers. However, when we delve further, we find that it is not a compound ecosystem. Several blockchains are available in the market, each with its unique attributes. Multiple chains are created with distinct use-cases in mind; therefore, they have unique strengths, limits, and degrees of decentralization. For example, if the goal of a certain blockchain is to attain a higher level of transaction throughput, the blockchain may have a lower level of decentralization and security.

Some blockchains largely exist in silos and therefore cannot communicate with others. This is exactly where cross-chain technology like Polkadot comes into play. It has a cross-chain architecture that facilitates interoperability through Parachains and bridges. Polkadot supports data transfer between distinct blockchains, providing robust security, scalability, and development.

Polkadot, like every blockchain ecosystem, represents the concept of a decentralized web in which a few major firms do not have control over how users interact with technology or the capacity to exploit users’ data security and privacy for personal purposes and motivations. All sorts of chains, including public, open, permissionless, and permissioned blockchains, are supported by Polkadot for data transmission.

Polkadot works as a layer-0 protocol and is a multichain network that lays the foundation for Web3 development. It comprises Parachains created using a primary blockchain SDK known as Substrate. Creating a custom blockchain using Substrate gives more freedom, flexibility, and efficiency than building on top of a general-purpose smart-contract blockchain. It helps develop blockchains based on Proof of Existence. “Proof of Existence” blockchain-based algorithm demonstrates if a digital document was there at a certain moment. A blockchain can establish a document’s existence without the aid of a third party, making it an effective alternative for a notary. The Substrate is, therefore, a robust software development framework for blockchain-based development. In this article, let’s explore Substrate and blockchain development in a detailed way.

What is Substrate?

The Substrate is an open-source, extensible and modular framework designed for building various interoperable blockchain networks like Polkadot. It is a Software Development Kit (SDK) created specifically to provide developers with access to all of the blockchain’s essential elements and free them up to concentrate on developing the logic that gives your chain its creative character. Substrate stands out from all other distributed ledger platforms by the following attributes:

  • Open
    The whole Substrate toolkit and architecture are distributed under an open-source license. The Substrate framework’s essential elements employ open protocols like libp2p and jsonRPC while giving you the freedom to build your blockchain architecture to your best ability. Additionally, Substrate has a sizable, helpful, and active building community that contributes to the ecosystem. As the community grows, more features become accessible for you to implement into your blockchain.
  • Flexible
    Most blockchain platforms include strongly linked sub-systems, inflexible and challenging to disconnect. A chain built on a fork of another blockchain can potentially have non-obvious couplings that fundamentally weaken the blockchain system.By choosing the network stack, consensus mechanism, or governance technique that works best for your project or by building your components, Substrate is a completely modular blockchain framework that enables you to assemble a chain with clearly separated components. One can set up a blockchain using Substrate that is tailored to your needs and can grow along with them as they change.
  • Future-proof
    The Substrate was designed to be flexible, modular, and upgradable. The Substrate runtime—the state transition logic—is a standalone WebAssembly object. Under some circumstances, your nodes can be given the authority to alter the Runtime itself, causing runtime upgrades throughout the network. As a result, “forkless” updates are feasible since, in most circumstances, no action is necessary for nodes to function with this new Runtime. The runtime protocols of your network may gradually, and perhaps dramatically, change to meet the demands of your users.
  • Interoperable
    Most blockchain systems only offer a small amount of interoperability with other blockchains. Cross-Consensus Messaging (XCM) enables all Substrate-based Blockchains to communicate with one another. To share the security of a relay chain, a parachain can be closely attached to a substrate to construct chains as autonomous networks (solo chains).

Why do you need Substrate?

The development of a blockchain is challenging. It requires complex technologies, which you must master to deliver a safe platform on which apps can function and which consumers can rely on, including advanced cryptography and distributed network communication. scalability, ownership, interoperability, and user-friendliness are creating challenges that need to be solved. For developers, the intricacy imposes a high barrier to entry. In light of this, the first query to be addressed is, “What do you wish to build?”

If you want to create a secure and advanced blockchain. Using Substrate, you can build a Blockchain platform that reflects the following:

  • Customized precisely based on the particular use case
  • Compatible connect and interact with different blockchain platforms
  • Tailored with pre-set sustainable modular components
  • Has the capability to evolve and get upgraded over time

The Substrate blockchain framework aims to be the best one for creating customized blockchains. The Substrate is more like a blockchain SDK framework than a standalone blockchain. Substrate offers the opportunity to design a chain empowering you to construct beyond what is achievable for others.

What programming language does Substrate use?

Rust is a dynamically compiled programming language with a comprehensive system and ownership concept that is very quick and memory-efficient. It enables developers to debug at compile time and can be used to power performance-critical services while ensuring memory and thread safety. Additionally, Rust offers excellent documentation, an easy-to-use compiler, and premium tools like integrated package managers and multi-editors with capabilities like type inspection and auto-completion. Rust stops all crashes, and it’s intriguing because it comes preconfigured as being secure, much like JavaScript, Ruby, and Python. Because we cannot create incorrect parallel code and you can never see a flaw in rust, this is far more powerful than C/C++. It represents many different programming paradigms quickly and accurately.

Rust is responsible for a large portion of Substrate’s extensibility and adaptability as a platform for developing mission-critical applications. The runtime and the outer node are two separate architectural elements that constitute the Substrate. Although more advanced Rust technologies like multithreading and asynchronous Rust are utilized in the outer node code, runtime engineers aren’t directly exposed to them, making it simpler for them to concentrate on the node’s business logic.

What is the relationship between Substrate and Polkadot?

The future of Web3 is being built around the layer-0 protocol and multichain network known as Polkadot. The main blockchain SDK used by programmers to build the parachains that constitute the Polkadot network is called Substrate. It is simple to incorporate substrate-based chains into Polkadot or Kusama to create a parachain or parathread. Substrate is essentially the SDK used to create parachains, while Polkadot is the tool used to protect the chains and enable communication between them. The seamless compatibility of all Substrate-based chains with Polkadot allows access to a wide range of resources, applications, and parachains.

Polkadot and Substrate are synergistic, although there are few alternatives for supporting development on Polkadot. For example, Polkadot parachains can be created and maintained without ever contacting Substrate, and chains created using Substrate do not require connection to Polkadot or Kusama. Substrate-based chains can exist independently as “solo-chains.”

To demonstrate its high degree of speed, versatility, and resilience, Parity Technologies utilized Substrate to build Polkadot, which enables you to develop customized blockchains for any use case.

While connecting to Polkadot has several advantages, including built-in security, cross-chain interoperability, and access to Polkadot’s expanding ecosystem of platforms, apps, and end users, connecting to any blockchain, not only Polkadot parachains, is possible using Substrate.

Now that we know the relationship between Polkadot and Substrate, let’s understand how Substrate powers the development of Proof of Existence Blockchain in the next section.

How to build a Proof of Existence Blockchain with Substrate?

Users can provide a file’s Proof of Existence with the below module. This Proof of Existence could also serve as a loose indicator of ownership. The blockchain does not directly accept file uploads. Instead, a file digest is created, then placed on-chain along with the user’s claim and the upload time. Anyone accessing the source file may create the same digest and verify the on-chain Proof of Existence.

Implementing the Currency trait is necessary for this module to function. The SRML Balances module can accomplish this:


Installation: Runtime Cargo.toml

Add the module to Runtime by including the following code to Runtime’s Cargo.toml file:

default_features = false
package = 'proof-of-existence'
git = ''  


Update: Runtime’s std

std = [


Implement trait: Runtime

impl poe::Trait for Runtime {
type Currency = Balances;
type Event = Event;

Now include this trait in the contruct_runtime! macro using the following code:

POE: poe::{Module, Call, Storage, Event},


View: Substrate PoE Reference docs

View the reference docs for this particular module by inserting the following code:

cargo doc --open


Polkadot, known as “the blockchain of blockchains” and a key element of the Web3 technology stack, requires a flexible blockchain development platform like Substrate. It simplifies blockchain development with no technical complexities. Hence, Substrate compels many blockchain developers to avoid using a restrictive and homogeneous smart contract environment that limits creativity and prevents using Polkadot’s extraordinary heterogeneous sharding technology.

Looking for Substrate development services? Connect with our Substrate and Polkadot experts to build the project of your dreams!




Author’s Bio


Akash Takyar

Akash Takyar LinkedIn
CEO LeewayHertz
Akash Takyar is the founder and CEO of LeewayHertz. With a proven track record of conceptualizing and architecting 100+ user-centric and scalable solutions for startups and enterprises, he brings a deep understanding of both technical and user experience aspects.
Akash's ability to build enterprise-grade technology solutions has garnered the trust of over 30 Fortune 500 companies, including Siemens, 3M, P&G, and Hershey's. Akash is an early adopter of new technology, a passionate technology enthusiast, and an investor in AI and IoT startups.

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