Implementing Multisignature on a Blockchain-based Land Administration System: Securing Land Rights and Enhancing Transparency

Ownership of land is a complex and multifaceted concept. Land distribution to all social categories is an even more difficult task, as in most cases we lack the instruments to capture land rights information on the ground. As part of the United Nations’s Sustainable Development Goals1 5 (Gender Equality) and 10 (Reduced Inequality), we must think of ways and means to not only capture the rightful owner of a land but also build the framework that will protect those rights regardless of the social categories of its owner. While, on the one hand, many initiatives have been taken to improve the traditional tenure arrangements and other legal aspects towards a more equitable land access distribution, in another hand the technology implication is still lacking. We argue that technology reinforcement is necessary to provide enough protection against corruption. In this paper, we propose to implement a blockchain-backed land administration system based on Hyperledger Iroha. Besides the blockchain’s inherent ability to resist corruption and enhance transparency, the proposed system would provide support for multi-signatory land transfer transactions. Such a mechanism would make sure that each shareholder agrees on any given land transaction, effectively protecting their right to the land.


INTRODUCTION
In many countries land access can be challenging.Some categories struggling more than others due to customs, laws, and gender biases.According to the Food and Agriculture Organization (FAO) [19], women own only 15% of agricultural land in sub-Saharan Africa, and many of these women only have access to land through their husbands or male family members.A report by the International Development Law Organization (IDLO) [29] highlights the various legal barriers that prevent women from accessing and owning land in Africa.These barriers include discriminatory laws that prioritize male inheritance rights, lack of legal documentation to prove land ownership, and limited access to formal land registries.To address these challenges, various organizations and initiatives are working to promote women's land rights and improve their access to land in Africa.These include legal aid programs, land tenure reforms that recognize women's rights to land, and women-led land governance and decision-making initiatives.
In addition to women, there are several other social categories that struggle with land access in various regions around the world.These include: • Indigenous peoples, who make up around 5% of the world's population, often face significant challenges in accessing and owning land due to historical and ongoing colonization, displacement, and exclusionary land policies.According to the International Land Coalition (ILC) [6], indigenous peoples and local communities hold only 10% of the world's land, despite having customary and ancestral rights to much of it.• Small-scale farmers, who are estimated to produce up to 80% [11] of the world's food, often face difficulties in accessing land due to increasing competition from large-scale commercial agriculture and land grabbing by corporations and investors.According to the International Fund for Agricultural Development (IFAD), small-scale farmers own or manage only about 25% of the world's agricultural land.• Rural communities, who often rely on agriculture and natural resources for their livelihoods, may also face challenges in accessing and owning land [28] due to limited formal land tenure systems, insecure land rights, and lack of representation in land governance and decision-making processes.
To tackle these difficulties, a comprehensive strategy is necessary, which encompasses legal and policy changes, community-driven land governance and decision-making, as well as assistance for small-scale farmers and marginalized communities to obtain resources and enhance their ability to efficiently manage and utilize land in a sustainable manner.To ensure the protection of land access from tampering, it is imperative to establish a reliable technological foundation on which to build these approaches.
Blockchain technology has emerged as a potential solution to address these issues.Multiple studies [10,13,33,37] have explored its use for land governance and management, highlighting its potential to improve land tenure security, transparency, and exclusivity.One significant advantage of blockchain-based land registries is their ability to create secure, tamper-proof records of land ownership and use rights.These registries can help prevent fraudulent transactions and disputes over land, while also improving land tenure security.For instance, Allen et al. [1] found that blockchainbased land registries have been successfully implemented in several countries, including Sweden, Georgia, and Ghana, resulting in improved land tenure security and reduced corruption.
In their report Makala and Anand [25] briefly discussed the potential of leveraging multisignature transactions on blockchain to protect the rights of spouses and indigenous people.In this paper, we propose an implementation of a blockchain land administration system that can help fight land access disparity by enabling multiple signature accounts.
The paper is structured as follows: The introduction is followed by a brief literature review on the possibility of using multisignature transactions on blockchain to fight land access disparity.Sections 3 and 4 present the system requirements and the proposed solution, respectively.In Section 5, we discuss key considerations for the implementation.Finally, Section 6 concludes the paper.

RELATED WORKS 2.1 Overview of multisignature in blockchain
Multisignature on the blockchain has been the subject of many studies.Some of them [15,39] focus on improving the scheme used, while others [7,14] explore novel ways of using it in specific domains.In fact, its use has grown as a way to divide up responsibility in the management of digital assets among a group of users.Besides, as noted by Fareed [8], it can be used to protect a user's access to their account.For instance, if we require a threshold of private keys for any operation, as long as only one key is compromised, the user would still hold access to their account.There are many ways of implementing a multisignature wallet on a blockchain platform.The most common way is to implement it at the smart contract level, as is the case for Ethereum [12].In systems where smart contracts are not supported, like Bitcoin, it is achieved through modification of the blockchain protocol.For example, the pay-to-script-hash was necessary for Bitcoin [4].Another example is Hyperledger Iroha 1, which did not have a complete smart contract implementation.However, it had a native support for multisignatures guaranteed by one of its building blocks, namely the Multisignature Transaction Processor [16].

Blockchain and land governance
The use of blockchain technology has been proposed as a potential solution to improve land administration around the world.One key advantage of using blockchain technology is the ability to create secure, tamper-proof records of land ownership and use rights, which can prevent fraudulent transactions and disputes over land.For instance, a study by Ameyew and de Vries [2] analyzed the implementation of blockchain-based land registries in Ghana and found that it improved land tenure security and reduced corruption.
Several studies have explored the potential of blockchain technology in addressing land access and ownership inequality.In a nutshell, most of the literature found regarding blockchain application to land governance revolves around the following subjects: • The feasibility, which is often assumed as a good starting point in any research area.We find, for instance, the paper by Müller and Seifert [27] for Germany's case.Other examples are the study by Vos [38] and the one by Lemieux [24].• The most suitable blockchain technology.We found various land administration implementation case studies in the literature using various private/consortium platforms like Hyperledger Fabric [26,35], Factom [24], Ubitquity [10], or public blockchain platforms like Bitcoin (for document validation [13] and Colored Coin [3]) and Ethereum [22,33].• The way of integrating blockchain into the land administration system.Some propose it to be added as a document validation layer like it was the case for Georgia [13].Others propose a new system that builds around the blockchain platform [37].And some have proposed the middle approach as an add-on to the existing system [20,35].• The usage of smart contract [23,26] to secure or automate part of the process.
A paper by Anand et al. [3], note that the multiparty signature feature or multiparty wallets of blockchain technology can be used to secure women's property rights in the context of marital property.Despite legal provisions guaranteeing women equal rights to land and property, anecdotal evidence suggests that these rights are often disregarded in practice.For instance, husbands may sell marital property without their wives' consent, thereby compromising their property rights.By enabling multisignature wallets, blockchain technology can provide a mechanism to safeguard women's rights to marital property.Additionally, multiparty transactions can be leveraged for property transactions that involve multiple owners, such as small-business loans where the joint property is used as collateral.
In summary, multisignature has proven its efficiency in resolving similar cases in other areas of application like supply chain [5] or finance where the technique was applied even before blockchain [34] for e-checks on joint accounts.Although the report Anand et al. [3] have pointed out the importance of enabling multisignature on blockchain to reduce the gap in land access and ownership inequality, being a report on opportunity and usage, it didn't expand on the specifics of that aspect.This paper is meant to fill that gap.We propose the usage of a novel blockchain technology for land administration that would ensure multisignature transaction support.We proceeded in building a sample network and client application to showcase its feasibility.It should be noted that the use of Hyperledger Iroha for land administration has not yet been documented in the literature.

REQUIREMENTS
This project focuses on one application of blockchain in land administration, namely the use of blockchain to enhance land right protection for disadvantaged social groups.The requirements for a blockchain-based land administration information system were well listed by Sladić et al. [33].They agreed that to establish a blockchain-based LIS (Land Information System), the following points should be considered: • Determine whether the blockchain network should be public or private and authorized, and how identity management will be handled.
• Define what data will be included in one transaction in the blockchain.• Determine how smart contracts will be used and what business logic should be implemented and executed on the blockchain.
Besides those points that have been largely discussed [33,35], in this case, we will focus on building a blockchain-based LIS that has the following features:

PROPOSED SOLUTION 4.1 Architecture
Giving the predominance of mobile platforms and it rapid adoption in web-based services [32,40] worldwide, we proposed an architecture that has a mobile platform as the end client.This client will be directly integrated with the blockchain network without a traditional back-end service.Hence the key pair will be generated in the participants' devices and resides there.Besides the regular participants, a special permission set will have to be implemented for land administration agent.Those participants would have the ability to issue the land titles (see Fig. 1).

The blockchain platform
In our study of the various blockchain platforms that were suitable for our requirements and system architecture, we found Hyperledger Iroha to be a promising and well-fitting one.Hyperledger Iroha is a graduated project from the Hyperledger Umbrella that aims at assets, information and identity managements [17].It supports multisignature transactions out of the box, provides a modular approach of permission and mobile platform SDKs.Its consensus  Assets are associated with accounts and can be transferred between them using transactions.Assets can be characterized by their Mintable parameter, their type (fungible or non-fungible) and their value type (see Fig. 2b for the available value).An asset is called mintable if we can produce more of them after the initial quantity was emited.• A signatory in Hyperledger Iroha is an entity or participant that has the authority to approve or reject transactions on the blockchain network.Each account can have multiple signatories associated with it, and transactions must be signed by the required number of signatories before they can be executed.That number is usually addressed as the quorum.
Iroha is made of several components Fig. 3 give a high-level view of how they could be organized based on the four-layer structure.

environment and network configuration
We built our project on an Intel I7-1185G7 @ 3.00GHz processor coupled with 32 g of RAM running a Ubuntu flavor OS.We bootstrapped a sample Iroha 2 network composed of 4 peers running on Docker with a custom genesis block.The genesis block allowed us to: • Define the domain of the land administration; • Create a pair of land administration office agents that have the permission to mint the assets, i.e., issuing land title • Create a default account that has the right to register new accounts.This account is used for first registration of users through the application.
• Register an asset definition for land title.It is defined as a nonfungible, mintable store assets type [16].A store asset type is a special type used to work with metadata.This metadata will allow unique characteristic of each piece of land to be captured in the blockchain.

Feature coverage
In this section we present the main feature that our platform support and how it does so.

Account enrollment.
The process of account creation is pretty straightforward as most of the work is done by the SDK embedded in the app.It is responsible for the user key-pair generation and submitting the transaction to the blockchain.The process is described in Fig. 4.
Listing 1: The asset Definition form the Genesis " Register ": { " NewAssetDefinition ": { " id ": " landtitle # landoffice ", " value_type ": " Store ", " mintable ": " Infinitely ", " metadata ": { " key ": { " String ": " Region " }, " value ": { " String ": " Region Name " }}}}  5a).To do so he will need the public key of the other parties.One signatory is added at a time (Fig. 5b) as under the box, each time we add a public key, the system mint it to the account.For this .mintPublicKey ( id .asAccountId () , publicKey ) buildSigned ( keyPair ) }. also { withTimeout ( timeout ) { it .await () } }} test purposes a MintBox was created, after all the account's signatory (represented by their public key) have been added (answering continue to the modal on Fig. 5c).It sets the SignatureCheckCondition of the account to ContainsAll.This evaluates the list of all the signatories added so far in the account and set the quorum to that number (Listing 3 provide a sample of a MintBox with two signatories).4.4.3Co-owned asset transfer.For an asset to be co-owned, it needs to belong to an account with multiple signatories added to it i.e., the quorum of the account is greater than one.By default if only one person signed the transaction to transfer such assets, the transaction will be stuck in a pending state.Under the hood when the application is run, it checks for every transaction pending that is waiting for the user signatures and list them under pending transaction for his approval(signature).Until the quorum is met, the transaction won't be committed.

Why Hyperledger Iroha?
Hyperledger Iroha 2 is one of the most versatile blockchain platforms.It can operate as both a public and private blockchain [16].This versatility allowed us to configure the right set of permissions.For example, we leveraged it to allow new land titles to be issued (minted) only by the land administration, while allowing anyone to become a member in our test network.
Among many other platforms, we also considered using another Hyperledger project: Hyperledger Fabric.It has been proposed several times in the literature [9,33,35].One of the main reasons we chose Iroha 2 over the other platforms is that it supports outof-the-box multi-signatory accounts.This feature is in accordance with our requirements (section 3).
In our setup, the keys and therefore part of the cryptography operations are handled client-side, as opposed to the usual setup we find in a private/hybrid blockchain where wallets are typically stored server-side.While one can argue about some inherent security risks of having a key pair stored in mobile devices, we've come a long way in electronic signature solutions in mobile devices [31].
Another useful built-in feature is the ability to delegate to another account the ability to transfer assets [16] (via the can_transfer_ my_assets permission).This feature allows proxies to operate on behalf of the owner.This is useful in legal frameworks where notaries are still required to handle land transactions, and can also be used for regular proxy-carried operations.In our sample application with Iroha Java SDK, this is simply done by registering a permissionToken of type CanTransferUserAssetsToken to the targeted account [16].
Regarding performance and scalability, since Iroha 2 is an ongoing project, we cannot yet make a fair comparison to other blockchain platforms.However, the performance goals of the project, as stated in its whitepaper [18], are 20,000 transactions per second (tps) and a block time of 2-3 seconds.The block time refers to the duration a node should wait after submitting a transaction to the leader for block creation before suspecting a potential faulty leader, triggering a view change, and electing a new leader [18].

Identity handling
In this study, we proposed self-enrollment of users.However, this approach needs to be studied more deeply.Iroha has been used for secure digital identity [36], and a similar approach could be coupled with the proposed solution.
Similarly, we could fine-tune the enrollment process to a more streamlined approach using a Public Key Infrastructure (PKI) solution with a front-facing Registration Authority (RA).This approach would allow us to link individuals to their wallets, as land properties can be utilized for money laundering.There is typically a strict requirement to adhere to Know-Your-Customer practices [35].Additionally, we would need to consider how the land administration accounts would be created.
Alternatively, the utilization of a blockchain-based identity management system, such as the one proposed by Pei and Oida [30], could enhance the overall robustness of the solution.

Conflict Mediation
While the use of a multi-signatory account is interesting, there is still a risk of conflict.For example, in the case of marital rights to a piece of land, it could happen that the spouses do not both agree on a transaction.The question of how to technically resolve such a case remains to be answered.In practice, these cases go to court, and a judge decides based on law and regulation how the situation should be handled.
One possible technical solution would be to add an additional signatory to each such account with a quorum set to 2. In that way, in the case of a dispute between spouses, the court would have an emergency account as a tool to enforce its verdict.Of course, the question regarding the integrity of the person in possession of the "tie-breaking" key can be raised.However, the blockchain keeping track of the signatories that allowed each transaction would serve as an audit trail.In the unlikely event of a corrupt court, the fear of leaving one fingerprint behind when signing should limit tampering.
There are more complex cases that require particular attention.We could further investigate the use of "conditional multi-signatory accounts" as a way to tackle complex cases.It could allow at least to implement a similar logic as the one with a quorum of 2. In the case of an arbitrary number of keys, we could set a policy that allows a transaction to proceed if a particular key (to be given to the justice system) signs the transaction or the defined quorum is reached.Still more work needs to be done to determine if such solutions are realistic.As of the time of writing, Hyperledger Iroha 2 does not yet support conditional multi-signatory accounts.

Cost Coverage
It is generally assumed that the cost of blockchain transaction mining will ultimately be borne by the end user.This is particularly true for transactions that are done or even anchored in a public blockchain.In Georgia's case [13], the first year of operation, all transaction fees were supported by Bitfury Group.The government then calculated the actual fee and its budget allocation to cover maintenance and operating expenses.It is still difficult to predict how the fee would fluctuate if we build on a public blockchain.
While the proposed solution is a hybrid one without anchoring to a public blockchain, we should adopt a similar approach to first determine the cost of running the solution.This solution would need to be first deployed by the public authority and define how new nodes would be created to maintain a good level of distribution.Financial institutions, conveyancers, and surveyors are good candidates to create and maintain independent nodes.These entities are already heavily involved in land transactions and already perceive benefits from people making land transactions.Provided that running the solution is not too cost-heavy and the Iroha 2 consensus performance [18] goals are reached, it is possible to lower the fee for the end user.

CONCLUSION AND FUTURE WORKS
In this paper, we have proposed a solution for improving land administration systems towards Sustainable Development Goals2 5 and 10, namely Gender Equality and Reduced Inequality.Our proposed solution utilizes multisignature accounts on a blockchainbased land administration system.We have made it mandatory for each transaction involving assets owned by such accounts to be multi-signed by a predefined quorum.For testing purposes and due to SDK restrictions, we were only able to set the quorum to the number of signatories (public keys) of the account.This ensures that any sale or transfer of land can only occur with the awareness and consent of all other right holders.
To demonstrate the feasibility of this solution, we designed a public permissioned blockchain using Hyperledger Iroha and developed a sample prototype.Our proposed solution offers enhanced security against corruption and fraud and provides a transparent and equitable land administration system.Using Hyperledger Iroha for blockchain-based land administration is novel as no known implementations have been found in the literature.Hence, our study also allows us to assess its feasibility.
Overall, we believe that our proposed solution can be an effective tool for addressing land ownership and distribution issues towards achieving sustainable development goals.Further research is necessary to test the scalability and efficiency of this solution in different contexts and to further study the aspects discussed in section 5. We also plan to work on integrating this system with other systems and tools like the UN-Habitat Social Tenure Domain Model (STDM) Tool and the FAO's OpenTenure software for capturing land rights information on the ground.These steps will further help consolidate the initial data that will be required for the genesis block.

( 1 )
Ability to create one's own account by easing the means of generating a key pair.(2) The ability to sell a property.(3) Ability to create a property with co-ownership.(4) The ability to sell a co-owned property by cosigning the property transfer transaction.(5) The ability to delegate the right to sell a land title to another account.