XCLAIM Commit

Proof of concept implementation of XCC.

External requirements

This implementation depends on an exchange rate oracle, and a Bitcoin SPV client.

• A mock exchange rate oracle is provided.
• BTCRelay can be used for SPV verification. (Mock is provided for testing and development.)

Structure and functionality

Paper link TBA.

XclaimCommit.sol

Keeps track of users, vaults, their balances and accounting. Implements registration, issue, redeem, collateralisation, checkpoints and hashlock management.

Validator.sol

Auxilliary contract used to assist in validation of Bitcoin transactions, including scripts, values, etc.

Building and deployment

• Build:

npx buidler compile

• Test:

npm test

• Regenerate docs:

npm run docs

• Deploy on a local buidler EVM:

npm run localdeploy

XCC Usage

Refer to docs for API details. A vault must be registered first, then a user can be registered with it. The user can then submit proof of a Bitcoin Issue transaction to get tokens created. These can then be collateralised by the vault (negotiation between user and vault happens off-chain), traded (once collateralised and the hashlock is revealed), redeemed, and included in a checkpoint (which releases collateral).

Recovery happens purely on Bitcoin. The contract does not implement deposit-based incentives as described in the paper, so stale tokens could potentially exist forever (though the only negative effect would be cluttering potential explorer/viewing frontends, as such stale tokens are not usable).