ERC-6956 Asset-bound Non-Fungible Tokens

ReviewERCcreated 2023-04-29requires ERC-165, ERC-721

Asset-bound NFTs anchor a token 1-1 to an asset and operations are authorized through oracle-attestation of control over the asset

Authors: Thomas Bergmueller (@tbergmueller), Lukas Meyer (@ibex-technology)

ERC-165 interface ids

Computed here as the XOR of the selectors each interface defines.

IERC6956 0xa9cf7635

`0x99a346af`	`anchorByToken(uint256)`	view
`0x20cac85c`	`approveAnchor(bytes,bytes)`
`0x5aa7ba8f`	`approveAnchor(bytes)`
`0x287a0c54`	`approveAuthorization()`	view
`0x22e26bf5`	`attestationsUsedByAnchor(bytes32)`	view
`0x15f75281`	`burnAnchor(bytes,bytes)`
`0x0cd53d5f`	`burnAnchor(bytes)`
`0x901637e2`	`burnAuthorization()`	view
`0x43f6805f`	`decodeAttestationIfValid(bytes,bytes)`	view
`0x16c99b79`	`tokenByAnchor(bytes32)`	view
`0xb97f592e`	`transferAnchor(bytes,bytes)`
`0x25ed3fdc`	`transferAnchor(bytes)`

Interfaces the spec defines alongside the core one, which an implementation may or may not carry.

`0x7cb70de5`	`attestationLimit(bytes32)`
`0x491776ca`	`attestationUsagesLeft(bytes32)`
`0x4002921c`	`attestationLimitPolicy()`

0x051c9bd8 anchorValid(bytes32,bytes32[])

Topic0 is the keccak256 hash of the signature, which is what a log filter matches on.

`0xfe4a69f7911ca79f9ffc289280b5a70eedc2957e98939565d0a5396687d9204f`	`AnchorApproval(address,address,bytes32,uint256)`
`0xe50623df1cea48c40d705b7a6d25fefb906a1efb35e2e705beaae8874ee013c6`	`AnchorTransfer(address,address,bytes32,uint256)`
`0xf1308b8e914792ca367aca95e5edcb055205ccb1cff16c794a85b5aaf0a259fc`	`AttestationUse(address,bytes32,bytes32,uint256)`
`0xa23e97503ca8c4a0237ff9ad0bcdd4642b7399c1571d1b9f54645ca422739662`	`OracleUpdate(address,bool)`
`0x9d72288c74709041d54a5b66d3c2b3bb32b770d42e1be03ac32f586f28b63dc5`	`GlobalAttestationLimitUpdate(uint256,address)`
`0x9ba239f9f503fd91c2d4c02554e4e30dd8434d5546b3a25fb0b15d56d3609993`	`AttestationLimitUpdate(bytes32,uint256,uint256,address)`
`0xaccba5123227ee0099525bcb31f8a273f3023ac9a4458d4804caecc1d69bf2ad`	`AttestationLimitReached(bytes32,uint256,uint256)`
`0x813e62061f661fc55f49e41911d374dee0b354ffd1ec9eb04dc18b07d6813804`	`FloatingStateChange(bytes32,uint256,uint8,address)`
`0xccf7149ae20933032262903106d212029317c574e9b3d8cf35691eba94bd8dda`	`FloatingAllStateChange(bool,address)`
`0x5d14c0727e865600a5bd0c79e5bb53019a08131062b817e34deda19d906db7c8`	`ValidAnchorsUpdate(bytes32,address)`

Proposals this one names in its requires field.