1 Introduction
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Providing an understanding on recent DLTs interoperability in VE environment.
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Describe the application of IOTA Tangle and RESTful Application Programming Interface (API) for DLT interoperability.
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Design a possible scenario where DLT interoperability is applicable in VE context to provide virtual services to clients in VE environment.
2 Related Research
2.1 Background of DLTs in Virtual Enterprise
2.2 Overview of DLT Interoperability in Virtual Enterprise
Interoperability Types | Description |
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Syntactic interoperability | Also referred to as structural interoperability focuses on enabling computer systems with different data structure to work in a common compatible format. Mostly syntactic interoperability can be achieved by using a common architectural design among computer systems with incompatible data structures. In the context of this study syntactic interoperability involves the ability of data to be accessible and reused by different stakeholders in VE by focusing on the issues caused by distinct representations, purposes, and methods. |
Semantic interoperability | This refers to the information model and data model employed by different computer deployed which manages the operational procedures within the enterprise. Besides, there may be different semantic employed by computer systems due to legacy procedure employed or incorrect information used among the systems. Hence, semantic interoperability provides a structure for interconnecting or integrating semantically different data models ensuring that the meaning of data exchanged between systems provider and requester have a common data meaning. Semantic interoperability is linked whether the platform-specific semantics can be maintained across DLT. |
Specification interoperability | Aims to broaden the semantic interoperability of computer systems by extending several enhancements in terms of higher-level of system integration. Specification interoperability aids in the method of information hiding and decrease in the reliance on low-level interoperability. Besides, specification interoperability expands the range of employed programming languages. Without the specification interoperability semantic interoperability will not be able to specify the differences in data properties. |
Organizational Interoperability | As in VE there are various companies that collaborate to support the running of DLT platforms. However, these enterprises are currently employing different DLT networks according to their personal enterprise needs. Organizational interoperability aimed at developing techniques that can aids cooperation among VE. Though the organizational interoperability cannot be exclusively achieved without improving individual enterprise specification, as well as semantical and structural interoperability. |
Platform interoperability | This refers to the technical interoperability. It involves the technical processes that enable integration among DLTs. This is because DLTs employ different consensus mechanisms which offers flexibility in VE selecting DLT framework. Enterprises are faced with various issues in terms of platform interoperability since there are different platforms developed for specific DLT networks, such as Hyperledger, IOTA Tangle, Ethereum, and so on, each having different versions or platforms requirements. This difference may result to drawback for developers in developing cross-DLT and digital platform integration. Thus, platform interoperability facilitates cross-platform communication without requiring prior extensive knowledge of any specific DLT platform. Therefore, heterogeneous digital platforms can be federated when platform interoperability is achieved to develop innovative DLT applications which can be utilized in VE and other domains. |
Network interoperability | This type of interoperability will provide a method for facilitating seamless end-to-end connectivity between computer systems in heterogeneous DLT networks. This is because DLT employs different distributed networks and heterogeneous infrastructure that comprises of multi organizations which provides digital services. |
Isolated interoperability | This comprises of isolated computer systems that have no means of establishing connection with other systems. This type of interoperability comprises of standalone computer system at the local level that can be manually integrated for the purpose of data interaction and extraction among the isolated systems. |
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The solution architecture should facilitate various types of DLT systems, such as private or public DLTs e.g. (Ethereum, IOTA, Hyperledger Fabric, etc.).
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The integrated external systems must not trigger a major disturbance to the DLT infrastructure that will require modification of the smart contract procedures or requiring frequent forking for new intercommunication within the network.
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The end-users should be involved in any manual processing.
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Any dependence on off-chain communications with external digital systems shall be minimal.
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The integration should not negatively impact the security or performance of the DLT networks.
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The DLT platforms such as IOTA should be in full control of their data and assets.
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The data transfer protocol employed should be technology-agnostic. Such that the interoperability solution needed should not require substantial changes in the destination and source networks.
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The DLT infrastructure should be able to integrate with digital system solution with marginal effort.
2.2.1 Existing Interoperable DLTs in Virtual Enterprise
2.2.2 Consensus Mechanism and Operability of DLTs
2.3 Exiting DLT Interoperability Solutions
DLT Interoperability Solutions | Description |
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The Chain-Based Interoperability | The chain-based interoperability approach mainly aims to improve interoperability among public DLTs, particularly for the applications of cryptocurrencies in enterprises. The chain-based utilizes token swaps, for example crypto-coin swapping, to exchange data among different DLT platform. According to Wang (2021) this approach comprises of sidechain, notary scheme, and hash-locks. |
Sidechains | Sidechains was proposed by Back et al. (2014), as secondary chains connected to blockchains through a two-way peg procedure. This approach involves locking the transferred data on the mainchain till they are generated in the sidechain (Alkadi et al. 2021). Sidechains are suggested as alternatives for improving the scalability of blockchain and processing of transactions simultaneously with the main DLT (Lohachab et al. 2021). The primary goal of the sidechain is to expand the functionalities of interoperable DLT networks to support the transmission of data between interlinked blockchain networks in a decentralized approach to ensure synchronization of tokens among two chains (Hewett et al. 2020). Sidechains may deploy their own consensus mechanism via a two-way peg which completely differs from the main DLT protocol employed (Wang, 2021). Thus, all data transactions associated with sidechains are mainly rooted in a locking data transaction in the main DLT. The sidechain approach provides an alternative to sharding technique by entirely relying on the data stored on the side chain and incorporating the data with the main chain only when locking and unlocking data transactions. Thereby offering improvements to the underlying DLT by taking over some of the transitioning load (Antal et al. 2021). Although, generating and managing sidechains is complex as it is designed to interlock two chains only. Connecting more “N” DLTs requires constructing “N-1” sidechains which eventually reduces the scalability of this approach (Alkadi et al. 2021). |
Notary Scheme | Notary schemes provides centralized data and assets exchanges between multiple DLTs. This DLT interoperability approach is the most convenient and easiest to employ. Although it is susceptible to centralization associated security risks and possible single point failures (Alkadi et al. 2021). Notary schemes employ a third trusted body as an intermediary between DLTs. Hence, the notary’s role is to validate the integrity and correctness of exchanged data to guarantee consistency among DLT. One substantial advantage of notary schemes is that it requires no additional change and is easy to deploy in enterprise (Wang and Nixon 2021). An example on the application of Notary scheme is deployment of Ripple’s ILP protocol. Notary scheme is mostly employed for cryptocurrency exchange and is the most adopted as a common solution in industries that use DLT. |
Hash-locking | This is another technique that helps DLTs to exchange data and assets without requiring a trusted third party. Hash-locking employs a digital signature verification and Hash-Time Locked Contracts (HTLCs) to achieve interoperability among DLTs. This approach is employed to facilitate cryptocurrency ecosystem among trustless parties for off-chain transactions and atomic swaps (Alkadi et al. 2021; Christodorescu et al. 2021). Overall hash-locking approach via HTLC aids locking of collateral funds or assets on both distributed ledgers to form a universal payment channel and issues the collateral funds as part of a final payment automatically at the payment channel’s termination time or manually by the participants (for instance in case of manual channel termination or a disagreement) (Christodorescu et al. 2021). The hash-locking method employed puts a time lock on data transactions so that both agreements are fully met (Wang and Nixon 2021). The tokens are lock up for a certain time on one DLT platform. The receiving user can unlock the tokens utilizing a secret which is communicated with him/her by the sender. However, this approach requires distributing a secret between the receiver and sender which may have some associated security risks. Besides, it requires the sender and receiver to be online during data transfer duration. This is similar to the one-time password (OTP) as such it provides a robust interoperable solution for future development (Alkadi et al. 2021). |
Atomic Cross-chain | An atomic cross-chain or swap is one method that supports users of different DLTs to exchange their data or assets in a trustless manner. In this approach data exchange is carried out using atomic swapping procedure that is employed to ensure consistency and integrity among different DLT networks. The term “atomic” is derived from database management systems, where an atomic data transaction or atomicity is restricted to a set of binary outputs (for instance, either 0 or 1). Hence the concept of atomic swap is adapted to a multi-DLT scenario as an atomic cross-chain swapping procedure. Generally, atomic swap is employed to achieve interoperability among multiple DLT systems (Madine et al. 2021; Wang and Nixon 2021). To attain the atomic procedure, the token transfer course must be in a self-governing and synchronized manner among the involved DLT without the support of a centralized body. However, an atomic swap often facilitates token exchanges mainly rather than data transfers. Also, this approach mainly requires a counterparty (of another DLT) who is eager to swap these tokens (Wang, 2021). Additionally, atomic token swapping procedures are not adequately self-inclusive to carry out tasks of decentralized applications (DApps) as the executable mechanisms in DApps may require more complex actions other than basic token transfers. |
Cross-chain Communication | Presently, each DLT platform works as an isolated system, and it is difficult to acquire external data as each DLT executes data transactions independently. Cross-chain communication protocols are crucial to achieve DLT interoperability. Cross-chain communication entails the transfer of data between one or more DLTs. A cross-chain communication approach refers to the method in which a pair of DLTs (consist of both intra and inter DLTs) interconnect to achieve a consistent status and synchronization among DLTs. A cross-chain scenario can comprise of different DLT systems, e.g., Ethereum and Bitcoin. This approach aims at accessing or exchanging functionality and data which is available in other digital systems. It typically comprises of two chains usually two chains (source and target). The source chain usually refers to the DLT that originates the data transactions, and the data transaction is sent to the receiving DLT (Belchior et al. 2021). However, a cross-chain communication approach mainly focuses on homogeneous DLTs, such as intra-chain scenario, for instance, Zendoo, Interledger protocol, etc. In most cases, it is difficult to achieve a cross-chain communication protocol, since different DLTs may deploy different network models, block sizes, consensus protocols, hashing algorithms, and confirmation times (Wang, 2021). |
Blockchain of Blockchains | Generally, DLT interoperability aims to create a generic communication scheme between DLTs, e.g., transmitting arbitrary data across DLTs in a trustworthy and decentralized manner (Wang, 2021). Blockchain of blockchains approach is a model that integrates different blockchains in an approach analogous to sidechains called bridges. In blockchain of blockchains approach each blockchain is linked to other blockchains across different distributed network either directly or through hubs (Rajnak and Puschmann 2020). However, this approach requires the interconnected blockchains to have the similar architecture. Besides, this approach entails additional transaction fees which may inhibit scalability on a global level (Alkadi et al. 2021; Belchior et al. 2022). |
Trusted Relay/Relay Chain | Trusted relay is a decentralized method that aids validators from source and target chains to authenticate, sign, and deliver data transactions between two DLTs. Sometimes, a trusted third party is used to perform the tasks of the decentralized verifiers. Trusted relays involve trusted parties that redirect data transactions from a source DLT to a target DLT, aiding end-users to specify arbitrary business logic (Belchior et al. 2021). To achieve DLT interoperability between different DLTs such as blockchain platforms. Relays are usually employed on smart contracts running on a target DLT i.e., the DLT which requires data from a source DLT platform. For example, Cactus implements multiple trusted third party to issue data transactions in several DLTs (Alkadi et al. 2021). Relay chain was first developed in the chain fibers scheme, which suggests the notion of cross-chain data exchange across a single relay chain and several similar chains grounded on decoherence and transaction latency to manage data transactions of multiple components of the system. Subsequently, different DLT systems including Cosmos and Polkadot have been improved on this basis, improving the original DLT architecture, facilitating DLTs to exchange assets and data within a variety of heterogeneous DLTs. Although trusted relay approach supports cross-chain integration to a specified extent, it does not address data privacy issues (Lan et al. 2021). |
Oracles | Oracles are technological solutions for addressing complex computational issues in distributed ledgers. Oracles can be seen as mechanisms that offer a secure connection between DLT platforms and external digital platforms. Oracles acts as a trusted network of entities or third-party body for DLTs. Thus, oracles can be utilized to provide integration from via different URLs, InterPlanetary File System (IPFS), or components responsible for operating more complex algorithms. Accordingly, oracles are responsible for ensuring data authenticity through authenticity proofs. The required data can be retrieved from external digital services and published back to the distributed ledger via callback transaction (Antal et al. 2021). Although, oracles are faced with issues which impacts direct response or requests issued by node users during mining operations. This is an issue in VE, and it leads to DLTs not able to access dynamic changing data such as stock prices, weather, etc. Also, oracle-based system may be prone to man-in the-middle attack or data tampering. Besides, oracles re-establish trusted third parties and the concept of centralization which is seen as an issue (Henninger and Mashatan 2021). |
Open Digital Asset Protocol | Open Digital Asset Protocol (ODAP) is seen as the first cross-chain integration protocol for handling multiple digital systems and assets for cross border data transactions. It leverages data or asset profiles (such as the data schema of an asset) and via gateways. The ODAP was proposed by the Internet Engineering Task Force (IETF) mainly to support asset and data transfer protocol that is deployed between two gateway systems. The process of transmitting data or an asset among DLTs is analogous to an atomic swap that locks data or asset within DLT and creates its representation in another digital platform (Belchior et al. 2022). |
2.4 Prior DLT Interoperability Approaches
Authors, year and Contribution | Aim | Key Findings |
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Belchior et al. (2022) developed a fault-tolerant middleware for blockchain interoperability. | A HERMES fault-tolerant middleware was proposed that connects blockchain systems based on the open digital asset protocol. | Overall findings from their study suggest that cross-chain data transactions can be attained firmly with HERMES, as far as the gateways are conforming with legal frameworks. |
Alkadi et al. (2021) researched blockchain interoperability in unmanned aerial vehicles networks-based systems. | The study provided a review on cross blockchain approaches to underline the latest developments in the field. | Findings provided a continuum of scenarios related to unmanned aerial vehicles networks that may influence the possibilities of cross-blockchain approaches. |
Belchior et al. (2021) carried out a review on blockchain interoperability. | The study aims to reveal that blockchain interoperability has a much wider continuum than cross-chain asset and cryptocurrencies transfers. | Findings provide support for technologies, open challenges, use cases, standards, and future directions in blockchain interoperability. |
Domalis et al. (2021) proposed a conceptual approach to achieve an interoperable and trustable decentralized service for cross-border eGovernance mainly citizen-centric. | An artificial intelligence-based solution was introduced that facilitates stakeholders to contribute to a decentralized network. | Supported efficient service delivery and data exchange to promote an efficient, cost-effective, secure, and interoperable service. |
Ghaemi et al. (2021) designed a pub-sub oriented architecture to enhance blockchain interoperability. | The study also proposes an innovative blockchain interoperability approach for permissioned blockchains based on publish and subscribe architecture. | The study tested different subscriber and publisher networks, such as Hyperledger Besu, an Ethereum client and two distinct types of Hyperledger Fabric. |
Ghosh et al. (2021) explored how to utilize public-private blockchain interoperability within closed consortium. | A decentralized architecture gateway was provided as an interface for public and private blockchain which supports interoperation. | A use case of Hyperledger Fabric and Ethereum comprising of three service providers that creates a consortium was formed for cloud technology provisioning. |
Kazemi and Yazdinejad (2021) developed an automatic benchmark support for multi-blockchain interoperability-based platforms. | The study explored the security and efficiency requirements of interactions among heterogeneous blockchains. In realization of multi-blockchain approach in achieving an interoperability platform that aims at connecting different blockchains. | Provides understanding on the trade-offs between different interoperability platform and their appropriateness for different system domains. |
Lan et al. (2021) examined how to enable confidential interoperability within blockchains based on trusted hardware. | The study provided a privacy safeguarding cross-chain system that enable confidential interoperability among blockchains. | The key contribution aimed at encrypting cross-chain exchange of data based on the relay chain with the support of trusted implementation environment and utilizing fine grained access mechanism to protect end-user privacy. |
Lipton and Hardjono (2021) conducted research on intra-and interoperability of blockchain. | Provided an overview of intra-and interoperability of blockchain. | Findings from the study recommended employing automatic market makers for intraoperability and atomic swaps and gateways for interoperability. |
Lohachab et al. (2021) conducted a review on interconnected blockchains towards the role of interoperability between different blockchains. | A layered architecture was developed for efficient development of methods and protocols for interoperable blockchains. | Findings also provides taxonomy and insight into the state-of-the-art of on interconnected blockchains. |
Madine et al. (2021) developed an application-level interoperability for blockchain systems. | The study proposed an application-based cross-chain interoperability service which support blockchain infrastructure for architecture to share data and inter-communicate. | The study employs a decentralized platform as a distributed translation layer that can communicate with multiple blockchain systems. |
Wang (2021) carried out a systematic review on the current development of blockchain interoperability by investigating practical schemes and general principles to achieve interoperable blockchain applications. | Discussed several challenges and potential directions to improve blockchain interoperability. | Findings from the study provided the state-of-the-art discussion to address interoperability of blockchains. |
Wang and Nixon (2021) provided discussion towards an architecture for blockchain interoperability based on trusted services. | The proposed interoperable architecture offers robust arbitrary support for blockchain systems based on Byzantine fault tolerance protocol. | Findings from the study provides an effective cross-chain transmission protocol to aid interoperable operations and atomic swaps between various blockchain systems. |
3 Method
3.1 Design Science Method
3.1.1 Problem identification and motivation
3.1.2 Specifying the objectives for a solution
3.1.3 Design and development
3.1.4 Demonstration and evaluation
3.1.5 Communication
3.2 Employed DLT Approach
3.2.1 Suitability of Direct Acyclic Graph (DAG)
3.2.2 Pertinence of IOTA Tangle in Virtual Enterprise
3.2.3 Applicability of RESTful API Gateway in Virtual Enterprise
4 Findings
4.1 Background of Case scenario
Layers | Description |
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Context | The context layer comprises of the modules that specify the concerns and main requirements of stakeholders within the VE. It also comprises of drivers, enablers, quality factors, and main goals of all partners within the consortium. |
Service | The service layer specifically describes virtual services provided by all partners within the consortium. Also, the service layer uses data from different platforms deployed by business actors. The services layer is mostly driven by the VE objectives, and which is aimed at achieving DLT interoperability with external digital platforms. |
Business (Virtual Enterprises) | The business layer highlights all enterprises involved in consortium that collaborates to provide various virtual services aimed at supporting the actualization of DLT interoperability. This layer is envisioned to include all stakeholders or actors that work together to provide a value-added service to clients. This will enable new constellations of VEs, easy creation of innovative services, innovative collaborative business models, and evolution of virtual services. |
Application and Data Processing (DApps) | The application and data processing comprise of all software systems utilized by partners to support the consortium. This layer entails different thematic, or distributed or centralized platforms applications deployed to support the provision of virtual services, such micro payment, e-trading, data analytics, etc. |
Data space | This layer gathers different types of data through such as open data (e.g., weather forecast, energy trading, etc.), real time data (e.g., sensor data, data from IoT, etc.), mobility data, data from social networks, historical data, etc. These collected data are stored and treated in the data space layer. Data space layer define the data, meta data, and data that support DLT interoperability and open innovations within VE. Also, in this layer all different data sources utilized by different digital platforms deployed by all stakeholders within VE are captured to support collaboration. |
Technologies | The technologies layer mainly encapsulates the hardware and software employed to support applications and data processing layer for achieving DLT interoperability. For example, micropayment technologies used by IOTA Tangle and other cloud-based technologies used by RESTful APIs, etc. Moreover, in the technologies layer some data processes are carried out on real time data generated from the physical infrastructures layer. |
Physical Infrastructures | Thus, the physical infrastructures layer involves all physical hardware infrastructures to support DLT interoperability. It mainly captures all metering devices, sensors, equipment, industry 4.0 machinery etc. deployed within the enterprises involved in the consortium. |
4.2 Deployment of IOTA Tangle and RESTful API
Layers | Interoperability Modules | Applicability |
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Context | ● DLT interoperable virtual solution | ● The main requirement is to achieve DLT interoperability with external digital systems. This is achieved by employing the direct acyclic graph IOTA Tangle driven by RESTful APIs. |
Service | ● Logs booked multi-modal journeys to IOTA Tangle ● Payment service (send and receive payments) via IOTA wallet ● Setup and fund IOTA wallet (e.g., via Devnet Tokens) ● Ensure logged data are private and only available for parties with the MAM channel key within the Tangle ● Logs payments made to IOTA Tangle ● Set receiving urban mobility transport provider data for IOTA Tokens | ● All virtual services provided by the virtual asset payment platform to support digital payment for seamless electric mobility as a service are captured in this layer as seen in Fig. 1. ● These virtual services are provided to the different stakeholders such as the clients and urban mobility transport provider. |
Business (Virtual Enterprises) | ● IOTA ● Client ● Infrastructure/data provider enterprise ● Urban mobility transport provider ● Other organizations | ● This layer encompasses the stakeholders that collaborates with to achieve the virtual asset payment platform. ● IOTA is the main partner in the VE, and it works with other organizations which provide data and external digital systems. |
Application and Data Processings (DApps) | ● Virtual asset payment platform (IOTA Token) ● IOTA Tangle backend ● External electric mobility platform (backend processing) ● External electric mobility platform ● RESTfulAPIs for client services ● RESTfulAPIs for urban mobility providers | ● The external electric mobility platform is utilized by the clients to book for virtual electric mobility services and is connected to the external electric mobility platform (backend processing). ● To achieve interoperability the external electric mobility platform (backend processing) sends processed data to the external electric mobility platform which is integrated with IOTA Tangle. ● Moreover, the virtual asset payment platform processes micro payment and provides the IOTA wallet status to the client. ● The virtual asset payment platform is also connected to the IOTA tangle backend which provides data for eMobility services via several RESTful APIs to ensure interoperability. |
Data space | ● Urban mobility database ● IOTA Tangle ● Cloud solution database | ● The urban mobility database stores all the data related to electric mobility services and is owned and governed by the infrastructure/data provider enterprise within the VE consortium. ● Also, IOTA Tangle captures geolocation data of all devices, sensors, and clients, encrypts, and publishes these data to be utilized by IOTA backend. ● The cloud solution database mainly stores Masked Authenticated Messaging (MAM) channel information. It also sends stored information to the IOTA Tangle. |
Technologies | ● Data integrity technology ● Micropayment technology ● Dedicated cloud solution ● GeoLocation API ● Micropayments processing API | ● In this layer real time data generated from IoT devices, sensors and metering devices deployed in the enterprises are transmitted to IOTA micropayment infrastructure. The data are transmitted MAM protocol which encrypts data stream. The data integrity technology adds privacy and integrity to data also via MAM within the IOTA’s Tangle. ● The micropayment technology facilitates micropayments processing for all seamless electric mobility services provided to the clients via RESTful API. ● Then, the dedicated cloud solution transmits the gathered data via MAM channel to be stored in IOTA Tangle. ● The GeoLocation API and Micropayments processing API, integrates with IOTA Tangle to ensure data integrity audit trail to guarantee integrity of micro payments. |
Physical Infrastructures | Urban mobility options | ● This layer captures all the available electric mobility services. Moreover, in this layer other green mobility options offered by the VE are provided. |
5 Challenges and Recommendations of DLT interoperability
Open issues | Description |
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Increased cost of deployment | Deploying a cost effective cross-DLT platform in VE context may be an issue. That is because most platforms developed in VE are commercial and the successful integration with DLT platforms will incur associated costs (Alkadi et al. 2021). For example, the price of the Ether cryptocurrencies is mostly not stable and may continue to increase (Madine et al. 2021). |
Non-existence of a controlling third party | Even though the decentralized nature of DLT platforms offers several advantages and lessens significant security risks, it is mostly vulnerable to 51% security attacks due to no central body as a governing body (Alkadi et al. 2021). |
Choice of cross-DLT technology | Regardless of the extensive efforts devoted to design secure and efficient cross-interoperable DLT platforms, the selection of the most suitable DLT for integrating different platforms within VE is still a critical challenge. Presently available cross-DLT platforms are faced with reliability, security, or efficiency problems. Therefore, it is inevitable to select the ideal DLT to external digital platform that reduces the risks while maintaining interoperability (Alkadi et al. 2021). |
Challenge associated in updating smart contracts | Some DLT such as blockchain utilizes smart contracts to automate data transaction between participants within the network. Since these smart contracts are saved within the immutable ledger, they cannot be updated, and thus external platform integration to support future interoperability is needed with a complete re-write of the smart contract (Madine et al. 2021). |
Reduced Upgradability | DLT platforms mostly do not support a future-proof and adaptable. For example, it is not easy to upgradable existing DLTs such as Ethereum-based smart contracts. Presently, some solutions have been suggested such as using deploying Truffle Migrations and proxies in ZeppelinOS to aid upgradability (Madine et al. 2021). |
Universal classification of DLT systems and public keys | There is presently no standard nomenclature to classify DLT systems in a universal unique manner. Additionally, a public key address may not be exclusive to one DLT platform. A business entity (e.g., an investor or client) may utilize the same public key at several different DLT platforms concurrently (Lipton and Hardjono 2021). |
Reduced storage and computational resources interoperability | These are major obstacles in the actualization of DLT interoperability in VE. Especially, because most consensus mechanisms employed by DLT platforms consumes energy. Also, maintaining a copy of the distributed ledger for all consortium members requires a large memory. Increasing the memory capacity while minimizing computational energy of DLTs will be effective to achieve lightweight consensus mechanisms that can support DLT (Alkadi et al. 2021). |
Security issues | Security weaknesses may develop if the distributed ledgers in the cross-DLT platform utilize the permissionless architecture. This may lead to decreasing the security level that was allowed by the permissioned DLT. Accordingly, certain DLT might be executed either as private or public, permissionless or permissioned. If integrated together to achieve an interoperable DLT eco-systems, the security level of the entire DLT eco-system will not be optimal (Alkadi et al. 2021). |
Standardized APIs for cross DLT token transfers | As previously stated, standard protocols are required to operate token-transfers across different DLT platforms in an approach that is equivalent to the economic worth represented by the token (Tönnissen et al. 2020). Works are ongoing to help define payloads, messages, and APIs for data asset transfers across DLT platforms (Lipton and Hardjono 2021). |
Actualization of cross-enterprise interoperability | Presently, in achieving interoperability across heterogeneous enterprises, such as finance-mobility interoperability, further understanding of application-driven parameters are needed including consensus algorithms, transaction formats, and DLT configurations (Madine et al. 2021). Hence, there is need for provision of a generalizable solution for cross-DLT interoperability capability within the DLT eco-system in various industries to further support adaptability. |
Limited protocols and forms | The deployed commitment protocols for data asset transfers within DLT platforms should be standardized based on existing used transaction payment systems (for example grounded on 2-phase commit). The deployed forms of commitment evidence need also to be standardized for different DLT platforms that utilize compatible or similar distributed ledger data structures (e.g., Quorum and Ethereum) (Lipton and Hardjono 2021). |
Interoperable operations and policies | The basic DLT structure comprises of different operations and policies that are employed to govern the distributed ledger. Digital platforms interacting with a particular DLT should be able to work based to these pre-defined rules which is difficult to achieve (Lohachab et al. 2021). |
Speed of data transaction confirmation | Every DLT platform has its own means of confirming data transactions. Therefore, each DLT platform there have different throughput and speed of data transaction which may generally impact the interoperability of DLTs. Moreover, other parameters such as the consensus mechanism and size of the DLT may also impact the speed of data transactions (Lohachab et al. 2021). |
Deployed permissionability and compatibility of DLT | This is seen as one of the key bottlenecks in the actualization of interoperable DLTs. The base of the DLT is proposed as public architecture. Nevertheless, there are other DLT architecture which are developed for consortium and private based networks which may impact the interoperability of these DLTs (Lohachab et al. 2021). Also, most DLT may not be compactable. For example, private permissioned and public permissionless DLT. This may hinder the interoperability of these DLT platforms. |
Cryptographic structures | Cryptography is the main aspect that supports DLT as a trustless distributed ledger. Though, in achieving interoperability, cryptography is associate with a lot of complexities. Since each DLT use distinct cryptographic hashing mechanism. As such the data transactions exchanging between DLT with two different cryptographically networks possess a challenge for DLT interoperability (Lohachab et al. 2021). |
Standardization challenges | DLT interoperability undoubtedly faces standardization challenges. This requires the need for a well-certified and authenticated standard to improve collaborations provided by international standardization association (Wang, 2021). But in practice the design of standards to accelerate interoperability among existing DLTs, as well to future possible ones is a still a great challenge (Madine et al. 2021). |
Anonymization | The idea of anonymity in DLTs relates to the anonymity of the participating user. This anonymization feature of DLTs can result to more complexity during formation of interaction between two semantically different DLT platforms (Lohachab et al. 2021). |