Interoperability is a key concern for many dApp developers. A dApp might need to interact with various other applications, tokens and even blockchains to fully provide its services. This interaction with multiple chains often comes with a host of challenges, including differences in protocols, data formats, consensus algorithms and more.

The Topos solution

Topos provides an elegant solution to these issues, as it offers an environment where dApps can seamlessly interact with multiple chains. The protocol allows developers to create interoperable dApps that can communicate and transact with other chains without having to deal with the intricacies of each chain.

The use case

A decentralized finance (DeFi) platform built on Topos could allow users to interact with different assets that exist on other blockchains, like ERC-20 tokens or even non-fungible tokens (NFTs). A user could potentially lend, borrow, trade and earn a yield on assets from diverse chains, all within a single dApp interface. This level of interoperability opens up new possibilities for dApps, making them more versatile, user-friendly and inclusive of the broader blockchain ecosystem.

With the rising number of blockchain ecosystems, the ability to perform complex operations across multiple chains has become a necessity. This includes operations that require the coordination and interaction of smart contracts on different chains, as well as operations that involve tokens or assets on various blockchains.

The Topos solution

Topos facilitates such complex multi-chain operations with its robust protocol. It allows developers to build applications that can perform intricate operations involving multiple chains, thereby expanding the application's potential functionality and reach. It allows this on a base of uniform security, in which all blockspaces are of equal security.

The use cases

A prime example of complex multi-chain operations could be a DeFi operation that involves a collateralized loan. In this scenario, a user may want to put up collateral in the form of tokens from one blockchain to secure a loan in tokens from another blockchain. The operation would require reliable communication and transaction across these different chains, ensured by the Topos protocol.

Another example could be a multi-chain game that involves assets (such as in-game items or characters) represented as NFTs on different blockchains. A game built on Topos could allow players to use and trade these assets within the game, irrespective of the blockchain on which the assets originally reside.

Security is one of the paramount concerns in the realm of blockchain technology and dApps. Applications often require sensitive or private information to function correctly. This demands a platform that guarantees data security while also providing the benefits of blockchain technology.

The Topos solution

Topos addresses this need by providing robust security features, particularly through the use of zero-knowledge proofs (ZKPs) and certificates for cross-subnet communication.

Topos makes use of ZKPs, particularly with its zkEVM component, to provide a layer of privacy and security that is exceptionally robust. The zkEVM allows computations to be validated off-chain (or on-chain) without needing to reveal the underlying data, making it ideal for applications that handle sensitive information.

Furthermore, the use of certificates in the Topos architecture provides another level of security for cross-chain communications. Certificates are a secure method to confirm that data sent from one subnet to another is accurate and has not been tampered with during transmission.

The use case

A healthcare application built on Topos could leverage the zkEVM and certificates to securely handle and transfer sensitive patient data across different systems, ensuring data integrity and patient privacy across systems. Similarly, finance applications could benefit from these secure mechanisms, to both protect personal financial information and preserve the transparency and traceability benefits of blockchain technology.

In the realm of dApps, applications often require unique logic and operations to function optimally. This is especially true for applications that operate in specialized or niche sectors. Topos provides a flexible and customizable platform that can cater to these unique requirements, making it an ideal choice for developers.

The Topos solution

The Topos protocol is designed to be modular and flexible, allowing for the integration of custom logic into the operation of dApps built on its platform. This is made possible through the use of subnets, individual blockchains within the larger Topos network. Each subnet can operate independently with its own consensus mechanism, which enables the subnet to accommodate custom logic specific to a dApp's operations.

The use case

A supply chain management dApp might require unique logic to track the movement of goods across multiple stages and parties. With Topos, developers can create a dedicated subnet implementing the custom logic necessary to handle these specific operations, ensuring the dApp functions optimally without having to conform to a one-size-fits-all protocol.

Additionally, the use of the Ethereum Virtual Machine (EVM) adds to the flexibility for customizable logic integration that Topos provides. Given the prominence of EVM in the blockchain space, many developers are already familiar with creating smart contracts using Solidity. This allows them to leverage their existing skills while benefiting from the added features and improvements offered by Topos.

Blockchains conventionally offer limited blockspace. This is partly because of the nature of their consensus, in which all validators are supposed to compute all transactions all the time.

However, some dApps may want to run large computations.

The Topos solution

The Topos protocol does not mandate the use of blockchains for the state machine in subnets. As long as the subnet conforms to the Universal Certification Interface (UCI), subnet administrators have freedom of choice regarding their state machine.

For instance, a subnet could be running a single EVM with a limited number of stateless smart contracts, and a zkEVM. Both could be highly optimized to the limited number of tasks they can handle.

The use case

A DeFi provider wishes to offer a platform for provable Black-Scholes option pricing. They implement it as a number of parallel EVM instances, each with the same single stateless smart contract. The sequencer orchestrates a number of specialized zkEVMs.

The cross-subnet messaging protocol would be the following:

• A cross-subnet message arrives in the Black-Scholes subnet with a transaction's event that has the parameters necessary for the computation.
• After verifying the validity of the message with the relevant certificate, the sequencer launches one of the available EVMs.
• The smart contract computes the option price using the parameters transferred, then emits an event with all input and output arguments necessary for identification.
• The sequencer calls one of the zkEVMs to generate a validity proof, includes it in a certificate targeting the origin subnet and then sends it over the TCE.
• Another service then sends the event to the origin subnet, where it gets verified against the certificate.

The origin subnet has in effect delegated the computation to another subnet, and received a provably valid computation result. Because all operations are stateless, the subnet can handle computationally expensive operations in parallel, and bundle them in a single certificate.