BYC and CRT

Both the BYC and CRT tokens are standard CATs. Their tail puzzles support creating new coins and burning coin balance.

BYC tail

The BYC tail listens for tagged messages from collateral vault coins, which indicate how much is to be issued or melted. It checks that the sender has a puzzle matching the collateral vault by looking up the hash in statutes.

CRT tail

When melting is attempted, the CRT tail checks that the action and amount are authorized by the surplus coin. For issuing, the tail confirms that it is either protocol genesis, authorized by the recharge auction or authorized by the announcer registry. Like the BYC tail, these puzzle hashes are checked against the list committed in STATUTES_APPROVAL_MOD_HASHES_HASH.

Correctness and test coverage

Tests are included for verifying the main operations, which are issuing and melting tokens with the approval of particular puzzles. We recommend including negative tests to confirm that minting is not possible. Additionally, we recommend testing the end-to-end flows with collateral vaults, recharge auctions, and so forth rather than simply the puzzle's execution with those parameters.