DEX contract and policy rules for matching/retiring assets

[anvabr]

Problem description

Environmental market participants need ability to 'reconcile' two sides of the environmental balance sheet, i.e. to match and retire pairs of assets they own.

Requirements

Introduce a Hedera smart contract with the following functionality

• Standard Registries (SRs) can register their tokens (of specific types - i.e. minted by specific policies) as a side for 'matching pairs' of tokens, specifying rules for what is accepted as the other side of the pair based on
  • Extendable list of SRs
  • Extendable list of policies and their versions by these SRs (specific numbers, ranges, or 'any')
  • Token properties, such as their nominal 'weight' etc
  • TBD
• Hedera accounts owning tokens can request to match a number of different tokens, which (after the assessment based on the rules above) would result in their retirement
• Smart contract must automatically verify the trust chain of tokens before executing the retirement operation
• TBD should anything be done in the Guardian Policy Engine?

Definition of done

• Smart contract is deployed on the testnet
• Documentation covers the usage of the contract for SRs and ordinary market participants

Acceptance criteria

Retirement of tokens operation is cryptographically verifiable, i.e.

• only valid tokens can be retired
• tokens can only be retired under the rules specified by SRs for both sides of the pair
• the event of retirement is visible in the chain history