EVM Support Solution

[hackfisher]

Latest discussion and solution:

• Replacing Account20(EVM Contract Address) to AccountID32 using hash_concat instead of directly hashing.
• For Account32(subkey) to AccountID20 conversion, using ```cut````
• Using eddsa for evm call instead of ecdsa, so we can sign evm related txs using polkadot{.js} exention or other polkadot.js private key provider
• EVM and Substrate toolchains support: For web3.js, metamask, web3 rpc, remix(solidity ide) etc, we might need to to some forking to support eddsa sign.
• User only need to care about AccountID32 address, developers might need to know AccountID20(evm address)

Question:

Can ecdsa and eddsa share same key pair(for easier wallet support)?

Refer:

Frontier: Using two separate crypto algorithm (eddsa for substrate runtime, ecdsa for evm inside?)
https://github.com/paritytech/frontier

Moonbeam:

Question: Will use ecdsa instead of eddsa(sr25519)? and H160? Could ecdsa have compatibility issues with Polkadot Parachain?

Substrate Seminar

https://www.crowdcast.io/e/substrate-seminar/9

[hackfisher]

https://wiki.polkadot.network/docs/en/learn-keys#why-was-ed25519-selected-over-secp256k1

[hackfisher]

Related: darwinia-network/darwinia#496

[wuminzhe]

the code of hash_concat maybe like this:

hash_concat(evm_address) -> subkey {
    return evm_address + blake2256(evm_address)[0..12]
}

[freehere107]

polkadot-js/api#2499 (comment)

[boundless-forest]

#334

[hackfisher]

This is deprecated solution, for latest update please see #334