BUG: Latest `aa-sdk` version cannot generate valid EIP712 signatures due to latest signature methodology change in `light-account` repo.

[encrypted8532 | mihir]

[REQUIRED] Environment

• Browser version:
• AA SDK version:
• Package:

"@alchemy/aa-accounts": "^1.2.0",
"@alchemy/aa-alchemy": "^1.2.0",
"@alchemy/aa-core": "^1.2.0",

[REQUIRED] Describe the problem

Recently, light-account was updated and new factories were deployed introducing a breaking change. (LightAccount Deploy Commit)
When the light-account was deployed, they were deployed with a change in smart account signatures breaking the current logic of generating signatures using all aa-sdk. (Signature method change commit).

What the Signature method change commit included was a change in methodology to verify signatures which isn't yet implemented in aa-sdk.

Old Signature Verification logic:

1. Accept digest and signature using isValidSignature method.
2. Use ECDSA or EIP1271 to verify signature against the digest.

The latest version of aa-sdk generates signature based on the above logic (Old Signature Verification Logic).

New Signature Verification logic:

1. Accept digest and signature using isValidSignature method.
2. encode message data based on EIP712 with an added type LightAccountMessage(bytes message) represented by a hash LA_MSG_TYPEHASH.
3. Hash the encoded message data and store it in messageHash.
4. Now verify signature using ECDSA or EIP1271 against the messageHash.

The current aa-sdk method signTypedData doesn't generate signatures based on above logic resulting in all isValidSignature call to return 0xffffffff (Invalid Signature).

How to reproduce:

Try to sign a Typed Data using smart account method signTypedData

Current Workaround:

Using old Smart Account factory which didn't include breaking changes. Past deployments can be found here.

[encrypted8532 | mihir]

Note: I'm working a PR to fixing it.

[Michael Moldoveanu]

Thanks for reporting and good catch! totally overlooked this on our end.

If it's helpful, I've been working on a new account impl that has to deal with the same thing here: https://github.com/alchemyplatform/aa-sdk/pull/248/files#diff-fd399725d38fbabb06e3a5e11c980b3f03c51374c3b3f6af4f1b85e1e063f547R57-R113

Since you're already working on a PR I'll let ya handle it so we don't duplicate work, but the above PR could be used as a reference for how LightSmartContractAccount should be updated to support signing 1271 messages while still signing UOs correctly

[encrypted8532 | mihir]

@moldy530
Thanks. I'll keep updating my progress and keep eye on your PR.

[Ajay Vasisht]

hey @codebuster22 did you ever submit that PR?

[Michael Moldoveanu]

this has been resolved