convert ethereum public key to substrate public key

Question

given a known ethereum public key, is it possible to determine a substrate public key for the same account (for the purpose of an airdrop)?

i believe that substrate keys are interchangeable across substrate networks so that donations sent to a public polkadot address could trigger an airdrop to the sender of tokens on a different (new) substrate chain. i believe that the donation-sender could access their airdropped tokens by creating an account on the new substrate chain using the same mnemonic as they had used to create the polkadot account.

for example:

• a polkadot account: 16q5vjQ3UZvfsxGRfupR3caacDEQxMAj1vgwVYWJaf1VBTc
• sends dot to recipient: 1x8aa2N2Ar9SQweJv9vsuZn3WYDHu7gMQu1RePjZuBe33Hv
• a bot monitoring donations to the recipient above, triggers an airdrop (of the new token) to the public hex key of the sender: 0x04721868f93b81470eeb505d4d476189fe6e78d7e3aaaabde081ea3c77f2107b (obtained with subkey inspect 16q5vjQ3UZvfsxGRfupR3caacDEQxMAj1vgwVYWJaf1VBTc)
• the sender accesses the new token by creating an account on the new substrate network using the same seed as they had used to create their polkadot account.

two questions:

• is the substrate example actually possible or have i made incorrect assumptions?
• could something similar be accomplished if an erc20 donation was made to a monitored erc20 address. eg: can a public substrate account id be derived from an erc20 account id and will the owner of the erc20 account be able to access the new substrate token using their erc20 account seed?

edit: i have seen How to convert a Substrate address to an Etherum address? which asks how to do the conversion in the opposite direction but i am looking for specific guidance on whether an ethereum account holder would be able to access a substrate account using their ethereum seed.

Answer 1

The EVM works in a sandbox with its own accounts (and mapped accounts). So it is possible to access all tokens within the EVM sandbox with a Ethereum signer, while EVM accounts cannot make a transaction with a substrate native signer.

I think this article might help you regarding the different signers’ relationship https://medium.com/astar-network/using-astar-network-account-between-substrate-and-evm-656643df22a0