EVM checks

What @bluprynt/sdk-chain-evm checks, step by step. For background, see the EVM page. For the report format, see Reading the report.

Methods

Method	Check	Reads chain state
signature / eip191	The signature over the stored message recovers to the wallet	No
signature / eip712	The typed-data signature recovers to the wallet	No
signature with no scheme	Treated as eip191 when the wallet is a 0x address	No
contract_signature / eip1271	isValidSignature on the wallet contract, at the block for the moment. At "verified", that's the recorded block	Yes
transfer / amount	The transaction succeeded, was sent from the wallet, and the asset is on the transaction's chain. For the native asset (slip44), its recipient and value match. For an ERC-20 token, the receipt contains a matching Transfer event	Yes
transfer / memo	The transaction succeeded, its sender and recipient match, and its calldata carries the memo	Yes
admin_manual	Not re-checkable. Reported as unverifiable	—

Contract signatures and transfers need chain state, so offline their proof is unverifiable with the reason online checks not requested. Ask for a moment to check them. A transaction mined after the moment's block is unverifiable at that moment with the reason record postdates this moment. The same applies to a contract signature whose recorded block is after it.

A contract signature or transfer is read on the chain it records (caip2), not necessarily the token's chain.

Authorities

• owner: the token's owner() returns the authority's address.
• Multisig (account_type: "multisig", of any type, including controlled_by): read as a Safe. The Safe's getOwners() and getThreshold() match the claimed signers and threshold. The threshold is compared only when the claim has one.

Authority types without a generic EVM check, such as controlled_by, are unverifiable at every moment and need no RPC. A verification backed by such an authority is unverifiable at every moment too, even when its proof result is valid. A moment before the record still reports record postdates this moment, and "verified" on a record with no moment reports no recorded moment.

Steps

The steps the EVM checker can report. Their names are exact.

Step	Where
wallet is the authority or one of its signers	proof
eip191 signature recovers to wallet	proof and each moment
eip191 signature recovers to wallet (scheme not recorded, assumed eip191)	proof and each moment, when scheme is null and the wallet is a 0x address
eip712 signature recovers to wallet	proof and each moment
verification's authority is listed for the token	proof, from verifyKyiToken and verifyKyiResponse
eip1271 isValidSignature on <caip2> at block <n>	Moments
claimed sender is the wallet	Moments (transfers)
transaction succeeded	Moments (transfers)
transaction sender	Moments (transfers)
transaction recipient	Moments (native transfers with a recipient, memo transfers with a recipient)
asset is on the transaction's chain	Moments (amount transfers)
transferred amount	Moments (native slip44 transfers)
matching ERC-20 Transfer in receipt	Moments (erc20 transfers)
calldata carries the memo	Moments (memo transfers)
Safe owners match claimed signers	Moments (multisig authorities)
Safe threshold	Moments (multisig authorities with a threshold)
token owner()	Moments (owner authorities)
on-chain lookup	Moments, when the transaction doesn't exist or a contract call reverts or hits an address with no code

Reasons

A failed step makes the result invalid with the reason <step> failed. These reasons leave a result unverifiable:

reason	When
proof material missing	The method lacks the fields it needs
scheme <scheme> is not EVM	A signature with a non-EVM scheme, or with no scheme on a wallet that isn't a 0x address
online checks not requested	A contract signature or transfer in proof. It needs a moment
admin_manual is not part of the public trust model	admin_manual verifications
no generic EVM check for <type>	An authority that is neither owner nor a multisig, such as controlled_by
asset <asset> is not supported	An amount transfer of something other than slip44 or erc20
record postdates this moment	The moment is before the record, its transaction's block, or its contract signature's block
chain has no block at or before this moment	The moment is before the chain's first block
RPC has no state for block <n>	A past block the RPC can't serve

Reasons from the SDK core apply on every chain. They're listed in Reading the report.

How a moment is read

Each moment is read at one block. For "now", that's the latest block. For a past instant, the SDK finds the last block mined at or before it with a binary search over block headers. The search runs once per distinct point in time for each token, and all checks for that token share it: once for "now" or a Date, and once per distinct verified_at or observed_at for "verified". A contract signature at "verified" is read at its recorded block_number, while its authority is read at the block for verified_at. If the chain has no block that early, the check is unverifiable with the reason chain has no block at or before this moment.

Past blocks need an archive RPC. A regular node keeps only recent state. When the RPC has no state for the block, the check is unverifiable with the reason RPC has no state for block <n>.

A result read on-chain has a position with the block and its time.