[Multisig] Transaction Cost

[kanniec826]

Multisig transaction should be higher that that of the regular transaction. And it should be at least (N+1) times than the regular transaction cost.

N= No. of signatures

Need to specify in UI when user is planning to do the transaction. (In case when their signatures are from different users/sources)

[kwunyeung]

Currently @calvinkei set the gas-adjustment to 1.5. This is the adjustment multiplier for enlarging the estimated gas. When the tx is posted to do gas estimate, there is no signature and signer info in the tx. The extra 0.5x of gas estimate is to compensate the difference between the final signed tx and the unsigned tx. I would suppose we can consider 0.5x for each pubkey in signer info. Hence, the gas estimate of a multisig transaction can be estimated as

gas = gas_estimate x ( 1 + num_pubkeys x 0.5)