This EIP extends EIP-55 by optionally adding a chain id defined by EIP-155 to the checksum calculation.
The EIP-55 was created to prevent users from losing funds by sending them to invalid addresses. This EIP extends EIP-55 to protect users from losing funds by sending them to addresses that are valid but that where obtained from a client of another network.For example, if this EIP is implemented, a wallet can alert the user that is trying to send funds to an Ethereum Testnet address from an Ethereum Mainnet wallet.
The motivation of this proposal is to provide a mechanism to allow software to distinguish addresses from different Ethereum based networks. This proposal is necessary because Ethereum addresses are hashes of public keys and do not include any metadata. By extending the EIP-55 checksum algorithm it is possible to achieve this objective.
Convert the address using the same algorithm defined by EIP-55 but if a registered chain id is provided, add it to the input of the hash function. If the chain id passed to the function belongs to a network that opted for using this checksum variant, prefix the address with the chain id and the 0x separator before calculating the hash. Then convert the address to hexadecimal, but if the ith digit is a letter (ie. it's one of abcdef) print it in uppercase if the 4*ith bit of the calculated hash is 1 otherwise print it in lowercase.
Benefits:
| Network | Chain id | Supports this EIP |
|---|---|---|
| RSK Mainnet | 30 | Yes |
| RSK Testnet | 31 | Yes |
| Project | EIP Usage | Implementation |
|---|---|---|
| MyCrypto | Yes | JavaScript |
| MyEtherWallet | Yes | JavaScript |
| Ledger | Yes | C |
| Trezor | Yes | Python and C |
| Web3.js | Yes | JavaScript |
| EthereumJS-util | Yes | JavaScript |
| ENS address-encoder | Yes | TypeScript |
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