Assign different ChainIDs to the different subnets

[adlrocha]

We currently use the same ChainID for all subnets in IPC:

lotus/build/params_spacenet.go

Line 156 in f081f21

const Eip155ChainId = 31415926

. While we have a different NetworkName according to the SubnetID of the subnet, there is no way to differentiate the different subnets by ChainID what could open the door to potential replay attacks.

In order to overcome this issue, we should make the ChainID for a subnet inferable from its SubnetID. We could use a similar approach to the one used by FRC42 to deterministically get a method number integer from a method name string.

[adlrocha]

Related discussion: filecoin-project/FIPs#301 (comment)
Related issue in Fendermint: consensus-shipyard/ipc#339
Related FIP: https://github.com/filecoin-project/FIPs/blob/master/FIPS/fip-0039.md

[adlrocha]

Rust implementation in Fendermint: consensus-shipyard/fendermint#115