types: support eth hex address on accounts (#502 )

* types: support eth hex address on accounts

* changelog

* doc update

* add note for keyring output

2020-09-08 10:57:49 -03:00

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Accounts

This document describes the in-built accounts system of Ethermint. {synopsis}

Pre-requisite Readings

Cosmos SDK Accounts {prereq}
Ethereum Accounts {prereq}

Ethermint Accounts

Ethermint defines its own custom Account type that uses Ethereum's ECDSA secp256k1 curve for keys. This satisfies the EIP84 for full BIP44 paths. The root HD path for Ethermint-based accounts is m/44'/60'/0'/0.

+++ https://github.com/ChainSafe/ethermint/blob/v0.1.0/types/account.go#L31-L36

Addresses and Public Keys

There are 3 main types of Addresses/PubKeys available by default on Ethermint:

Addresses and Keys for accounts, which identify users (e.g. the sender of a message). They are derived using the eth_secp256k1 curve.
Addresses and Keys for validator operators, which identify the operators of validators. They are derived using the eth_secp256k1 curve.
Addresses and Keys for consensus nodes, which identify the validator nodes participating in consensus. They are derived using the ed25519 curve.

	Address bech32 Prefix	Pubkey bech32 Prefix	Curve	Address byte length	Pubkey byte length
Accounts	`eth`	`ethpub`	`eth_secp256k1`	`20`	`33` (compressed)
Validator Operator	`ethvaloper`	`ethvaloperpub`	`eth_secp256k1`	`20`	`33` (compressed)
Consensus Nodes	`ethvalcons`	`ethvalconspub`	`ed25519`	`20`	`32`

Address formats for clients

EthAccounts have can be represented in both Bech32 and hex format for Ethereum's Web3 tooling compatibility.

The Bech32 format is the default format for Cosmos-SDK queries and transactions through CLI and REST clients. The hex format on the other hand, is the Ethereum common.Address representation of a Cosmos sdk.AccAddress.

Address (Bech32): eth1crwhac03z2pcgu88jfnqnwu66xlthlz2rhljah
Address (EIP55 Hex): 0xc0dd7ee1f112838470e7926609bb9ad1bebbfc4a
Compressed Public Key (Bech32): ethpub1pfqnmk6pqnwwuw0h9hj58t2hyzwvqc3truhhp5tl5hfucezcfy2rs8470nkyzju2vmk645fzmw2wveaqcqek767kwa0es9rmxe9nmmjq84cpny3fvj6tpg

You can query an account address using the Cosmos CLI or REST clients:

# NOTE: the --output (-o) flag will define the output format in JSON or YAML (text)
ethermintcli q auth account $(ethermintcli keys show <MYKEY> -a) -o text
|
  address: eth1f8rqrfwut7ngkxwth0gt99h0lxnxsp09ngvzwl
  eth_address: 0x49c601A5DC5FA68b19CBbbd0b296eFF9a66805e5
  coins:
  - denom: aphoton
    amount: "1000000000000000000"
  - denom: stake
    amount: "999999999900000000"
  public_key: ethpub1pfqnmkepqw45vpsn6dzvm7k22zrghx0nfewjdfacy7wyycv5evfk57kyhwr8cqj5r4x
  account_number: 0
  sequence: 1
  code_hash: c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470

# GET /auth/accounts/{address}
curl -X GET "<NODE_IP>/auth/accounts/eth1f8rqrfwut7ngkxwth0gt99h0lxnxsp09ngvzwl" -H "accept: application/json"

::: tip The Cosmos SDK Keyring output (i.e ethermintcli keys) only supports addresses and public keys in Bech32 format. :::

To retrieve the Ethereum hex address using Web3, use the JSON-RPC eth_accounts endpoint:

# query against a local node
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_accounts","params":[],"id":1}' -H "Content-Type: application/json" http://localhost:26664

Next {hide}

Learn about Ethermint transactions {hide}

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