Is signature on the same typed message+same account stable in MPC?

If different co-signers participant in the typed message signing(the same message content), will the signature change? Is typed message signing using ECDSA?

Hi @peterp

Alec from Fireblocks here. No, the signature will not change for the same message and address, regardless of the signing parties. We support two typed message formats: ETH_MESSAGE and EIP712, both of which are signed using ECDSA.

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Hi @alec ,
Thanks for your reply. Does it mean that the same address hold a stable private key regardless the signing party changs? And for typed message signing, it is ECSDA not threshold ECDSA, right?

All the human and API co-signers on your Fireblocks workspace contain equivalent key material, so when the same message is signed via MPC, regardless of the co-signer involved, the signature is the same every time. In practice, Fireblocks caches the result of typed message signing, so if you request to sign the exact same typed message, the signature will be returned without the signing process being performed.

Yes, we do not use threshold ECDSA.