In this paper, we define an auction protocol and implementation of a decentralized and distributed auctioning platform for demand-supply matching of components and materials subject to recycling. Auctioning is the process of buying and selling goods or services by offering them up for bid, taking bids, and then selling the item to a winner according to preset rules. Some auction types relies on sealed-bids while others implement an open-bid procedure that allows for multiple bids before a known or unknown deadline. The English auction and its variants is most common type. It relies on that the current highest bid is always available to potential bidders. Online auction platforms are nowadays used to trade various services and goods. We address the iterative negotiations in form of auction bids aiming at signed contractual agreements stated in legal prose and captured by Ricardian contracts. We evaluate our model towards requirements including privacy, transparency and fairness in terms of acknowledged publishing of highest bids and the ordered arrival of individual bids. In addition, we demonstrate the mechanisms for distributed storage of cryptographically signed Ricardian contracts, omitting the need for trusting the auctioneer or relying on a trusted third party for this storage.

In this paper, we define a multi-attribute auctioning system for the circular economy and the trade of products, components and materials subject to recycling. The increasing popularity of auctioning systems for buying and selling goods has led to the adaptation of them to diverse and particular scenarios, many of which require support for attributes like delivery time, quality, etc. Such attributes allow for more explicit and precise negotiations than traditional auctioning systems where only price is taken into account. The circular economy concept replaces end-of-life with the reuse of various goods, aiming to keep as much value as possible of any asset. By allowing users to adjust attributes in multi-step negotiations according to their economic and ecological needs, better deals can be achieved. We address this potential with our multi-attribute, and multi-step auctioning system. The system is based on transparency and fairness principles, and addresses requirements for flexibility in what attributes can be used, and the need for a semi-transparent auctioning procedure. We present a winner determination approach based on scoring protocol based on weights for different input attributes. Our auctioning system uses a signature chain data structure to provide transaction traceability. We demonstrate using a generic example that the proposed system supports simple and flexible multi-attribute auctions.

Data is important for the industry to take advantage of digitalization, realize automation, assure quality, and more. Values from data are not only created individually by companies, but also in eco-systems in which data is shared among participating organizations. Secure data sharing is essential in such eco-systems to prevent unauthorized access and use of the data. Usage control extends traditional access control with restrictions concerned with requirements that pertain to data processing contractual obligations, rather than data access provisions only. Thus, usage control is relevant in the context of intellectual property protection, compliance with regulations, and digital rights management. This paper presents a method to negotiate contractual obligations and access provisions, and automatically enforce those provisions with access control. Finalized negotiations establish Ricardian contracts at two levels; a superordinate level with a connected subordinate level. These contracts contain provisions in terms of access control attributes. Using our implementation of a negotiation engine we demonstrate the automatic creation of NIST Next Generation Access Control (NGAC) access control policies. Our negotiation engine uses a lightweight model for the storage of an unforgeable and immutable log of the established contracts based on digital signatures and hashing.

An electronic auction (e-auction) is an efficient negotiation model that allows multiple sellers or buyers to compete for assets or rights. Such systems have become increasingly popular with the evolution of the internet for commerce. In centralized auctioning systems, the presence of a governing third party has been a major trust concern, as such a party may not always be trustworthy or create transaction fees for the hosted auctions. Distributed and decentralized systems based on blockchain for auctions of nonphysical assets have been suggested as a means to distribute and establish trust among peers, and manage disputes and concurrent entries. Although a blockchain system provides attractive features such as decentralized trust management and fraud prevention, it cannot alone support dispute resolutions and adjudications for physical assets. In this paper, we compare blockchain and non-blockchain decentralized auctioning systems based on the identified functional needs and quality attributes. We contrast these needs and attributes with the state-of-the-art models and other implementations of auctioning systems, and discuss the associated trade-offs. We further analyze the gaps in the existing decentralized approaches and propose design approaches for decentralized auctioning systems, for both physical and nonphysical assets, that support dispute resolution and adjudication based on collected evidence, and dispute prevention based on distributed consensus algorithms.

Open-cry electronic auctions have revolutionized the landscape of high-value transactions for buying and selling goods. Online platforms such as eBay and Tradera have popularized these auctions due to their global accessibility and convenience. However, these centralized auctioning platforms rely on trust in a central entity to manage and control the processing of bids, e.g., the submission time and validity. The use of blockchain technologies for constructing decentralized systems has gained popularity for their versatility and useful properties toward decentralization. However, blockchain-based open-cry auctions, are sensitive to the order of transactions and deadlines which, in the absence of a governing party, need to be provided in the system design. In this paper, we identify the key properties for the development of decentralized open-cry auctioning systems, including verifiability, transaction immutability, ordering, and time synchronization. Three prominent blockchain platforms, namely, Ethereum, Hyperledger Fabric, and R3 Corda were analyzed in terms of their capabilities to ensure these properties for gap identification. We propose a solution design that addresses these key properties and presents a proof-of-concept (PoC) implementation of such design. Our PoC uses Hyperledger Fabric and mitigates the identified gaps related to the time synchronization of this system by utilizing an external component. During the chaincode execution, the creation and submission of bids initiate requests to the time service API. This API service retrieves trusted timestamps from NTP services to obtain accurate bid times. We then analyzed the system design and implementation in the context of the identified key properties. Lastly, we conducted a performance evaluation of the time service and the PoC system implementation in time-sensitive scenarios and assessed its overall performance.

Linked data allows for general modeling and traversal of complex relationships based on web technologies. In industrial manufacturing and supply chains, centralized tracing of included components, materials, and parts of products still prevails, motivated by the manufacturer's needs to ensure data persistence, resilience against failures, and maintaining data ownership and security. This means that the detailed internal composition of a product containing complex parts from different suppliers will be in different silos and not easy to traverse. There is an opportunity for better-detailed interconnection between manufacturers and suppliers by providing globally decentralized solutions.

However, most existing decentralized traceability solutions focus on unidirectional linking for reverse traversal to find the origin of product parts. There is a need for bidirectional traceability in supply chains. While reverse traversal is needed to find compositions, forward traversal allows for acquiring information on what is produced from a certain item and which other product(s) it becomes part of. Establishing links for both forward and reverse traversal in decentralized architectures, which emphasize data persistence and consistency, is challenging.

The Interplanetary File System (IPFS) serves as a peer-to-peer data network for decentralized storage of data nodes. It can be augmented with additional tools to enable mutability and enhance its functionality.In this paper, we present a proof-of-concept (PoC) implementation based on IPFS and the InterPlanetary Name System (IPNS) to provide decentralized storage of linked data with forward and reverse relationships to provide bidirectional traversal capabilities. IPNS is used to create mutable pointers that reference IPFS stored data. This combination enables the creation of dictionaries or ledgers containing traces of events.Lastly, we present a qualitative evaluation of the PoC implementation in the context of supply chains.

In recent years, there has been a significant rise in the importance of traceability, particularly concerning the origins and manufacturing processes of specific products. This heightened emphasis on traceability has been driven by governmental and corporate initiatives aimed at advancing circular economy strategies. Digital Product Passports (DPP) are regarded as a prominent tool to enable decentralized cross-sectorial data connections. A DPP is a data set that summarizes the components, materials and chemical substances in a product which is complemented and information on repair events, disposal instructions, and environmental impact information. 

Gathering such information is a highly complex cross-sectorial endeavor. The requirements and standards on how data shall be designed and shared need to be clearly stated to achieve sustainable benefits. Semantic modeling using open standards can provide the DPP system with a shared knowledge of domain-specific structures for how data should be created and what queries can be performed. Moreover, the intricate data interconnections and traceability requirements require the enabling of bidirectional tracing of products, actors, and resources. The Interplanetary File System (IPFS) in combination with Resource Description Framework (RDF) allows for the decentralized storage of structured data. This can then be complemented with IPNS for the traversal of interconnected data nodes. 

This paper presents a Proof of Concept (PoC) comprising several microservices: The DPP management system which uses IPFS for decentralized data storage and IPNS for bidirectional traceability. The DPP definition system that utilizes semantic modeling technologies to standardize and provide cross-sectoral knowledge on design standards for the implemented passports. Furthermore, we utilize RDF-based ontologies for collecting decentralized interconnected data. This approach allows for semantic querying using the SPARQL protocol, thereby enhancing the system’s ability to retrieve and analyze data.