In order to achieve a sustainable society, efforts to create a circular economy are expanding. In Europe, a digital product passport (DPP) is being introduced to this end. Similar initiatives are underway in Japan, and NEC is participating in the Cabinet Office's Strategic Innovation Creation Program to promote the construction of a plastic information distribution platform, commonly known as PLA-NETJ. PLA-NETJ will provide an information distribution platform with enhanced data reliability by utilizing NEC's trust technology. In the future, the scope of the project will be expanded from plastics to various products and materials, and the goal is to achieve a circular economy by supporting the supply chain through information distribution.

1. Introduction

As economic globalization advances, various social issues are becoming increasingly evident, such as resource depletion caused by population growth, environmental impacts from waste, loss of biodiversity, and human rights issues like child labor. These challenges call for an economic system that can adapt to evolving social structures.

To address these issues, efforts are accelerating to rethink the linear economy of mass production, mass consumption, and mass disposal, and to create a sustainable circular economy (Fig. 1). A circular economy seeks to maximize the value of resources and products, minimize resource consumption, and reduce waste generation while promoting economic growth and job creation. Successfully navigating this transition requires encouraging behavioral change among businesses and consumers and creating a societal framework for sharing information about resource circulation.¹⁾

2. Circular Economy for Plastics

2.1 Challenges in Japan's Plastic Recycling

In the context of efforts to achieve a circular economy, the method of processing collected plastics has become a global issue. In Japan, the recycling rate of collected plastics is high at 87%, but 62% of it is incinerated as thermal recycling (Fig. 2). Although Japan classifies this process as recycling, it does not align with international standards. When measured against these global benchmarks, Japan's effective recycling rate falls to 25%, ranking it below many European countries.²⁾

2.2 The State of DPPs in Europe

The European Union (EU) is ahead of the rest of the world when it comes to implementing a series of strict environmental regulations to achieve a circular economy. The introduction of the Digital Product Passport (DPP) is making headway as a tool to enforce these regulations.

In Europe, the rules and mechanisms for a data space called GAIA-X⁶⁾, which enables data collaboration across countries and organizations, are being developed, and DPP information exchange will take place on a data space compliant with GAIA-X. In particular, the construction of Catena-X, a data space targeting the automotive industry, is progressing ahead of schedule.

2.3 Participation in SIP Phase 3 and the PLA-NETJ

To enhance interoperability with European data spaces, Japan’s Ministry of Economy, Trade and Industry has led the establishment of the Ouranos Ecosystem,⁷⁾ an industrial data space designed to enable data exchange between companies. Areas of　focus include batteries, plastics, base metals, construction materials, and home appliances.

As part of this effort, in fiscal year 2023, the Strategic Innovation Promotion Program (SIP) Phase 3, overseen by the Cabinet Office, launched the theme of “Circular Economy System Development (SIP-CE). In SIP-CE, NEC is playing a role in the construction of the Plastic Information Distribution Platform (PLA-NETJ) for communicating plastic information (Fig. 3).

3. Plastic Information Exchange Platform (PLA-NETJ)

3.1 Overview

PLA-NETJ is a system for managing and sharing information about the plastic materials used in products, ensuring traceability through the circulation of digital certificates (DPPs) that record various data. PLA-NETJ makes the entire life cycle visible, from raw and other materials, to the manufacture and distribution of parts and finished products, to the collection and recycling of products after use (Fig. 4).

DPPs include fundamental product details, comprehensive management data, certifications, regulatory compliance records, due diligence information, material composition, and historical tracking data. Each product’s DPP is linked to the DPPs of its individual components and materials, forming an interconnected supply chain information network (Fig. 5). With this linked data, businesses can precisely trace key details throughout a product’s lifecycle, such as where raw materials were mined, where they were processed, where final products were made, how much CO₂ was emitted, how much recycled material was included, and information on durability.

When implementing and managing DPPs in the supply chain, three major challenges must be addressed:

To address Challenge 1, PLA-NETJ adopts a distributed architecture that allows the issuer of the DPP to selectively disclose information (section 3.2). For Challenge 2, NEC applies trust technologies to authenticate data sources and prevent tampering (section 3.3). Finally, to overcome Challenge 3, PLA-NETJ is designed with future interoperability in mind, facilitating integration with industry-wide data spaces for secure cross-company data sharing (section 3.4).

3.2 Data Management Through a Decentralized Architecture

PLA-NETJ is designed to enable businesses issuing DPPs to retain full ownership and actively manage their data. To facilitate this, NEC proposes an architecture that integrates DPP issuance and management functions into each company's internal systems. Identity management for these functions will be handled through decentralized identifiers (DIDs)⁸⁾ (Fig. 6).

DIDs are a type of ID that is decentralized and managed by the service users themselves, as opposed to traditional IDs that are centrally managed by service providers.　The PLA-NETJ Center issues and manages Verifiable Credentials (VCs) ⁹⁾　based on user registration requests from businesses, ensuring that the entity is an approved user of the PLA-NETJ platform. Each business can verify these VCs to mutually confirm that its data exchange partners are legitimate PLA-NETJ users.

The DPPs issued by each business are stored and managed within the business and exchanged with other businesses on a peer-to-peer basis as needed. In addition, the issued DPPs are registered in the PLA-NETJ Center with only the public information, and the hash values are stored in the blockchain to manage the audit trail.　DPPs are formatted in JSON and are signed and issued with electronic seals (e-seals) and timestamps. When exchanging DPPs between businesses, it is crucial to control the disclosure of specific data items according to the relationships and conditions between the parties. To achieve this, the use of techniques like Selective Disclosure for JSON Web Token (SD-JWT)¹⁰⁾ are being considered for controlling the selective disclosure of data items. In SD-JWT, data items are replaced with digest values and signed, allowing only specific data items to be disclosed. This allows for signature verification without altering the signature, enabling selective disclosure of certain data items while maintaining the reliability of the DPP through signature verification (Fig. 7).

3.3 Trust Technology

Ensuring the reliability of DPPs involves implementing mechanisms to verify that the data recorded at issuance remain unaltered. To achieve this, PLA-NETJ employs e-seals certified by government agencies, along with timestamps, to digitally sign DPPs.

The e-seals¹¹⁾ serve to authenticate the legitimacy of the issuing organization or company, while the timestamps¹²⁾ provide assurance that the data existed at the time of issuance and have not been changed since. By managing the issued DPP evidence on the blockchain, its reliability is guaranteed (Fig. 8).

3.4 Integration with Data Spaces and Other Systems

PLA-NETJ is designed to connect with the industrial data space Ouranos Ecosystem, led by Japan’s Ministry of Economy, Trade, and Industry (METI), as well as DATA-EX, a platform for data sharing across various industries. This integration is achieved by using common interfaces, known as data space connectors, which facilitate seamless data exchange across industries and borders.

Additionally, by integrating with other systems such as the recycled material databank being developed by Tohoku University under SIP Phase 3, the electronic manifest system operated by the Japan Waste Research Foundation (JWNET), and the matching platform that facilitates supply-demand matching for recycled plastic materials, PLA-NETJ aims to create a mechanism that enables smooth utilization of recycled materials within the supply chain (Fig. 9).

4. Conclusion

As interest in sustainability continues to grow, the provision of reliable and transparent information throughout the product supply chain is becoming increasingly crucial for both businesses and consumers. In response to this demand, PLA-NETJ provides an information distribution platform that uses various trust technologies to enhance data reliability. PLA-NETJ enables businesses to properly disclose the information that their business partners and consumers are looking for, and we expect that this will enhance the value of their products and businesses. In addition, while PLA-NETJ's SIP-CE activities focus on plastics, they can be applied to other products and materials, and we are considering expanding the scope of our activities to include metals such as aluminum and copper, chemicals, and textiles in the future. By supporting the supply chains of various materials and products through the dissemination of information, we aim to realize a circular economy.

5. Acknowledgements:

This work is partially conducted under the Cabinet Office’s Strategic Innovation Promotion Program (SIP) Phase Three, focusing on the issue of Circular Economy System Development (JPJ012290).

References

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