EIP-7702 authorization nonce logic

[ArielGueta]

I'm working with the new EIP-7702 authorizationList feature. While using the library to sign authorizations via signAuthorization(), I noticed that the nonce used in the signature changes depending on who is broadcasting the transaction.

Relevant excerpt from viem's source:

authorization.nonce = await getTransactionCount({ address, blockTag: 'pending' });

if (executor === 'self' || executor.address === account.address) {
  authorization.nonce += 1;
}

This seems to suggest:

If the signer is also the one broadcasting (i.e., executor: 'self'), viem adds +1 to the nonce.

Otherwise (e.g., a relayer is broadcasting), it uses the current nonce from eth_getTransactionCount.

My questions are:

Should the authorizationList nonce match the EOA’s transaction nonce (getTransactionCount)?

Why does viem increment the nonce by 1 only when the signer is also the broadcaster? Why is the behavior different when another account broadcasts the transaction?

[jxom]

Why does viem increment the nonce by 1 only when the signer is also the broadcaster? Why is the behavior different when another account broadcasts the transaction?

In the case if Alice is the authorizor and the executor: The transaction will consume a nonce (alice:n), and then, the authorization will check against nonce of Alice (alice:n+1).
In the case if Alice is the authorizer, and Bob is the executor: The transaction will consume a nonce (bob:n), and then, the authorization will check against nonce of Alice (alice:n)

[ArielGueta]

Thanks for the response.

the authorization will check against nonce of Alice (alice:n+1).

But based on the source code of EVM, it first check if the authorization nonce is equal to the authorization account nonce. If the transaction is broadcast with nonce 3, the check will be with number 3 + 1 (4), no? What am I missing?

https://github.com/bluealloy/revm/blob/main/crates/handler/src/pre_execution.rs#L228

Thanks

[jxom]

it first check if the authorization nonce is equal to the authorization account nonce

This check is performed after the transaction nonce check: https://github.com/bluealloy/revm/blob/main/crates/handler/src/handler.rs#L183 (note that apply_eip7702_auth_list is after validate_against_state_and_deduct_caller.

[ArielGueta]

I see, but I don't understand why the nonce should be incremented by one? the current transaction nonce is set to 4 and the authorization nonce is 5 ( 4 + 1 ). So the check is 5 != 4, no?

if authorization.nonce() != authority_acc.info.nonce

[ArielGueta]

Never mind I now understand. Thanks for your help!