Global accountant: Message signature format doesn’t follow guidelines for guardian key usage

[tbjump]

Status Quo

The Guardian key is being used to sign a JSON message about an observation to be submitted to the Accounting contract.

Issue

The signature format doesn’t follow the recommendation of the whitepaper, which is to prepend a message type identifier of >=34 bytes.

Recommendation

In this line of code:

[wormhole/accounting.go at 7f512425dcf5425957c6921ed130caa9569023ab · wormhole-foundation/wormhole](

wormhole/node/pkg/accounting/accounting.go

Line 330 in 7f51242

digest := ethCrypto.Keccak256Hash(ethCrypto.Keccak256Hash([]byte(b64Bytes)).Bytes())

)

I propose that instead of computing digest := Keccak256Hash(Keccak256Hash(observation)), compute digest := Keccak256Hash(ACCOUNTING_OBSERVATION_PREFIX + observation) , where ACCOUNTING_OBSERVATION_PREFIX = ACCOUNTING_OBSERVATION_00000000000

The corresponding changes also need to be made in the Accounting contract.

Finally, this additional guardian key usage should be documented in the Whitepaper https://github.com/wormhole-foundation/wormhole/blob/main/whitepapers/0009_guardian_key.md

[aadam-10]

implemented in #2322