Proposal for smart-contract address generation

[paouvrard]

Currently a smart-contract address is generated from a hash of the creator’s account and the creating transaction’s nonce, prefixed with the byte 0x0C to arrive at a compatible length of 33 bytes : https://docs.aergo.io/en/v0.12/specs/addresses.html

In a near futur, users will be able to hold assets on different aergo sidechains and will most likely use the same private key to interact on those different chains.

Therefore a user might end up creating contracts with the same addresses on different chains.

Apart from possible confusion, and mistakes due to calling a contract on the wrong sidechain, other applications like multisigs and merkle-bridge would benefit from contract addresses being unique accross sidechains.

Currently, the merkle-bridge POC and standard-token use a custom contract id to prevent replay accross sidechains :
https://github.com/aergoio/merkle-bridge/blob/837e78d7bc87efaafec09b37ce96217efe505667/contracts/merkle_bridge.lua#L70

https://github.com/aergoio/merkle-bridge/blob/837e78d7bc87efaafec09b37ce96217efe505667/contracts/standard_token.lua#L45

But it would be better for applications that make use of signed nonces (multisigs, state channels ...) not to have to worry about creating a custom contract id for sidechain replay protection.

We can instead generate the contract address from Hash(sender_address + nonce + chainIDHash).