4.2 TRUST ASSUMPTIONS FOR TSX FOR PCF
We have seen that there are multiple parties in the entire eco-system for TSX for PCF , which can broadly be classified into certifiers , manufacturers , suppliers , auditing authorities and end customers . The roles of the VC model are evident as explained in the previous section . However , we need to have some trust assumptions .
Certifiers are the trusted third parties and other participants trust them to ensure proper behaviour within the TSX network . They are the trust anchor that vet the manufacturer ’ s processes and aid in issuing credentials that can be trusted by everyone within the TSX network . Certifiers are also trusted to follow the applicable standards and regulations in the LCA of products for PCF calculation .
The verifiers , whether they are manufacturers , the end customer , or some auditing authority assume that the certifiers are trustworthy . Furthermore , the credential owners are assumed to trust the certifiers for producing correct credentials , and that it reflects the true PCF value .
Additionally , it is assumed that the PCF values are linked to the corresponding real-world product and provide its accurate PCF . Lastly , for TSX for PCF , we also assume that the verifiable data registry is up-to-date , and integrity protected , and only authorized entities can post on the verifiable data registry .
5 EXEMPLARY APPLICATION OF CREDENTIAL ISSUANCE AND SHARING
VC technology is core element of the TSX for PCF process . Once a manufacturer starts building a product for its customers , it is commonly built with products from other suppliers . Figure 2 shows an example product of a Programmable Logic Controller ( PLC ), which requires among other things a plastic housing , which is sourced from one or more suppliers .
Figure 2 . The figure shows the process of sharing PCF credentials with a customer that uses a product in its manufacturing process . The VC for a PCF is issued by trusted issuing authorities that make sure that the PCF is being calculated according to the defined processes .
The list of all components describing the final product is referred to as the Bill of Materials ( BoM ). When the manufacturer calculates the PCF of its PLC , it iterates through the BoM , reaches out to
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