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KIP Title Author Status Type Category Created
0019
Coin-v6 and fungible-v3
Robert Soeldner (robert@kadena.io)
Draft
Standard
2023-05-02

Abstract

The next iteration of the coin contract proposes three main changes to enhance the maintainability and security of the contract.

Firstly, the rotate function, which is responsible rotating an account guard in a contract that implements the fungible-v2 interface, will be removed. In the case of fungible tokens that also implement the fungible-xchain interface, this will result "correct by construction" cross-chain transactions by avoiding the risk of locking funds sent to the receiving account.

Secondly, the constants and some functions within the contracts will be reorganized to increase maintainability (see Rationale). This is intended to make the codebase more structured and easier to maintain, reducing the chances of errors and improving the overall quality of the contract.

Finally, verification related code of the coin contract will be modified to allow for formal verification. This will enable rigorous proves of the contract's code to ensure its correctness and reliability. By incorporating these changes, the new iteration of the coin contract aims to provide a more secure and efficient platform for the exchange of cryptocurrencies.

Motivation

The presence of the rotate function in the current implementation of the contract undermines the integrity of cross-chain transfers. Specifically, executing the rotate function before the completion of a cross-chain transfer can result in the locking of funds.

Moreover, the utilization of our formal verification system can significantly enhance the security of the contract. Therefore, necessary changes to allow the verification of the contract are introduced.

Timeline

The KIP process has a time constraint of 1.5 months, which will end on June 30th AoE, during which participants are expected to share their feedback.

Date Event
2023-05-02 Publication of initial document
2023-06-30 Deadline of KIP-0019

Rationale

Changes within fungible-v3.pact:

  • Model annotation for the schema account-details: Add new invariant expressing positive balance (>= balance 0.0).
  • Model annotation for defun get-balance: Add new property that != account "" and >= result 0.0.
  • Model annotation for defun details: Add property that the account is not empty != account "".
  • Model annotation for defun enforce-unit: Add property that the amount is not negative >= amount 0.0.
  • Model annotation for defun create-account: Add property that the account is not empty != account "".

Changes within coin-v6.pact:

  • Change the fungible-v2 interface to fungible-v3.
  • Bless old coin contract (coin v5).
  • Move constants (COIN_CHARSET, MINIMUM_PRECISION, MINIMUM_ACCOUNT_LENGTH, MAXIMUM_ACCOUNT_LENGTH, and VALID_CHAIN_IDS) to a different section.
  • Move utility functions (enforce-unit, and validate-account) to a different section.
  • Replace enforce (!= sender ... by validate-account in defun DEBIT and CREDIT.
  • Remove defcap ROTATE
  • Add additional enforce to express that gas consumtion must be greater than zero (enforce (> total 0.0)) within defun redeem-gas.
  • Enforce the refund unit enforce-unit refund within defun redeem-gas.
  • Add validate-account to defun get-balance.
  • Add validate-account to defun details.
  • Within fund-tx enforce a valid miner within the defpact step.
  • Add invariant >= balance 0.0 for the allocation-schema.

Backwards Compatibility

N/A

Specification