Digital twins tokens for traceability: Blockchain Layer
About the protocol
Tokens use as digital twin closes a gap on the use of blockchain tokens used for traceability while reducing blockchain deployment complexity. This article presents how tokens are used to protect the information integrity along with the supply chain and represent product ownership between supply chain stakeholders. This design solution stores information on blockchain tokens and transaction metadata and uses a common ontology to create interoperable data. This low tech solution enables a collaborative secure environment to exchange open source information.
About the blockchain
Blockchain technology is a digital ledger of transactions replicated at several geographically distant nodes, thus it is distributed across an entire network of nodes that uses some consensus protocol to bring eventual consistency, i.e. every node in a network will reflect the same state. Information is stored by creating transactions, broadcasted through the node network. Every node will check the transaction and if valid will be included in a block with the signature of the wallet.
After Bitcoin and Ethereum, Cardano is part of the third generation of blockchain. Via the extended unspent transaction output (EUTxO) Model [28], Cardano blockchain allows for the implementation of minting policy at the token minting that can make every token unique. As for Ethereum, Cardano also allows abstractions of transactions thus allowing to add metadata to the transactions
Cardano uses PolicyID to protect the minting and modification of the token. The PolicyID is a 24 words seed phrase that creates a hash and defines the token minting policy. Cardano policy ID can be used to directly identify the token issuer since the seed phrase is really hard to recover from the hash.
Another particularity of Cardano system is the use of staking addresses and receiver/sender addresses that belong to the same wallet. This unique staking address can be retrieved from receiver and sender addresses.
About the digital twin based on blockchain token
Digital Twin is a digital representation of a physical product that mirrors its states, behaviour, position across the supply chain.
- Data structure
Digital twin requires data about an object or process in order for a virtual model to be created that can represent the behaviours or states of the real world item or procedure. Blockchain tokens are chunks of information stored on the blockchain that can use the IPFS file system to attest a file ownership. Blockchain tokens can create Digital Twin store in metadata (text information structure in a JSON like format).
Product specific standards can be chosen to design products. This data standard should be adopted by the supply chain stakeholders in order to efficiently reused the information and make interoperable digital operation. Due to the JSON format, short and concise encoded information are preferred to efficiently use machine verification and avoid misinterpreting.
- Tokens bound
Digital twins can be linked to create a more complex system of relation and services. A digital twin of a certification can be directly bound to the digital twin of a food product via a metadata bound that can attest the product quality, certification, test, origin that serve as proof.
This bound is encoded and specialised to understand the link between tokens. For example, FoodOn ontology used “certified”, “has part”, “has quality” to qualify relation between elements. The token policy ID will serve to identify the token provider efficiently thus policyID must come from a third party certification recognized by stakeholders in order to create trust on the document and on the product.
- Modelling
Once the data has been gathered it can be used to create computational analytical models to show operating effects, predict states such as fatigue, and determine behaviours.
Tokens keep the information integrity of a product from cradle-to-grave and at every transfer or transformation. Moreover, minting and trading tokens in stoichiometric quantities can help to track the quantity produced and distributed backward and forward along the supply chain. This end-to-end quantity preservation will prevent introduction of fake products in the supply chain. At the end of the product life cycle, the token must be sent to a decided burning address to prevent the token being reused for counterfeiting activities.
Transaction metadata can efficiently report the operation made on a product and follow a standard for interoperability along the supply chain. Metadata labels that contain a numeric value can be encoded to contain the type of transaction, (for example “Transfer to cold chain/retailer/storage/manufacturer” . Metadata content is a short string (64char) that contains the product change . This metadata content can point to an IPFS folder (for example: “QmTkzDwWqPbnAh5YiV5VwcTLnGdwSNsNTn2aDxdXBFca7D”) that will contain immutable information about the product. Following a standard this metadata content folder could describe product transformation (physical/ chemical changes), contain information generated by IoT about the product environment (light,temperature,humidity) or transport (vehicules,location, duration) shared between stakeholders. The transaction metadata content can also point to a private server or contain a hash of the information to maintain privacy.
At the product transformation, the process should also be stored in metadata bound and obey to a metadata standard. The burning transaction of the token refers to the policyID of the manufactured product. The manufactured product will be bound with the raw material (part/parent) token (such as “as part”) by referring to the token burning transaction. Part tokens will be burned and the manufactured token will be produced in stoichiometric quantity. These two mechanisms will protect information integrity during the product transformation.
About DT use in traceability
Traceability is the ability to record and keep history of a product from the production to consumption while answering “when, where, whom?”.
In the blockchain all transactions and wallets are stored on the blockchain and possess unique addresses. Blockchain helps to store the product trace by keeping the information on the ledger by the physical owner of the asset. This authentication brings more certainty and interoperability on the data stored about the asset, in turn that becomes more valuable.
Usually a customer will scan a tag (QR Code or NFC) applied on a product to access its traceability information stored on the blockchain. By verifying information customers are involved in anti counterfeiting products, verifying the trace and preventing them from harmful fake products.
If blockchain can efficiently help regarding the system traceability, permissioned blockchain solutions come with several drawbacks. If the blockchain validators are from the same actors such as permissioned solution then there is a high risk of adversarial attack removing the benefit of immutable storage. Moreover, data on this chain is not available and cannot be used by consumers and governments. This lack of accessibility blocks the transparency about the social and environmental impact of the supply chain and the interoperability of information along the supply chain.
Digital twins help for products to be synchronized to one different database by querying the same blockchain. Using metadata data standards in token and transaction, tokens improve the interoperability between database and application. It removes the cost of data architecture and development making the blockchain traceability more accessible.
Digital twin tokens can be support product traceability. At the product transfer, the transaction differentiate a lot of products from another lot. Thus every lot of products can be identified by a unique transaction. From the most recent transaction, a digital twin can be traced back to the minting transaction, allowing a product auditability. This unique latest transaction can be integrated in a QR code (for example ‘6bfe43e4ec5242d82fb18419eac21b4098c099b2fb11bada9280a97eccab049a’) for consumer to check the physical product full traceability. All Stakeholders participants are identified by their wallets staking address or policyID. To help this identification a system based on users wallet should allow them to add information to clarify the role of every participant in the supply chain and enforce transparency and auditability.
About Living Roots:
We want to develop this technology for agricultural product and help smallholders farmers. To improve our product traceability transparency and help farmers to build more sustainable farming and receive fair contributions. Living Roots work to improve this development and principles with different stakeholders and apply this principle in the food sector to help smallholders farmers access communication channels, rental systems and access to markets with easy to deploy blockchain token solutions.
Join us to develop a fair and transparent food system!
