Accounts

Crypto Wallets (or Accounts) can be created and represented in unique ways on different blockchains. For developers who interface with account types on Slinky, e.g. during wallet integration on their dApp frontend, it is therefore important to understand that accounts on Slinky are implemented to be compatible with Ethereum type addresses.

Prerequisite Readings

• Cosmos SDK Accounts

• Ethereum Accounts

Creating Accounts

To create one account you can either create a private key, a keystore file (a private key protected by a password), or a mnemonic phrase (a string of words that can access multiple private keys).

Aside from having different security features, the biggest difference between each of these is that a private key or keystore file only creates one account. Creating a mnemonic phrase gives you control of many accounts, all accessible with that same phrase.

Cosmos blockchains, like Slinky, support creating accounts with mnemonic phrases, otherwise known as hierarchical deterministic key generation (HD keys). This allows the user to create accounts on multiple blockchains without having to manage multiple secrets.

HD keys generate addresses by taking the mnemonic phrase and combining it with a piece of information called a derivation path. Blockchains can differ in which derivation path they support. To access all accounts from a mnemonic phrase on a blockchain, it is therefore important to use that blockchain's specific derivation path.

Representing Accounts

The terms "account" and "address" are often used interchangeably to describe crypto wallets. In the Cosmos SDK, an account designates a pair of public key (PubKey) and private key (PrivKey). The derivation path defines what the private key, public key, and address would be.

The PubKey can be derived to generate various addresses in different formats, which are used to identify users (among other parties) in the application. A common address form for Cosmos chains is the bech32 format (e.g. slinky1...). Addresses are also associated with messages to identify the sender of the message.

The PrivKey is used to generate digital signatures to prove that an address associated with the PrivKey approved of a given message. The proof is performed by applying a cryptographic scheme to the PrivKey, known as Elliptic Curve Digital Signature Algorithm (ECDSA), to generate a PubKey that is compared with the address in the message.

Slinky Accounts

Slinky defines its own custom Account type to implement a HD wallet that is compatible with Ethereum type addresses. It uses Ethereum's ECDSA secp256k1 curve for keys (eth_secp265k1) and satisfies the EIP84 for full BIP44 paths. This cryptographic curve is not to be confused with Bitcoin's ECDSA secp256k1 curve.

The root HD path for Slinky-based accounts is m/44'/60'/0'/0. Slinky uses the Coin type 60 to support Ethereum type accounts, unlike many other Cosmos chains that use Coin type 118 (list of coin types)

The custom Slinky EthAccount satisfies the AccountI interface from the Cosmos SDK auth module and includes additional fields that are required for Ethereum type addresses:

// EthAccountI represents the interface of an EVM compatible account
type EthAccountI interface {
	authtypes.AccountI
	// EthAddress returns the ethereum Address representation of the AccAddress
	EthAddress() common.Address
	// CodeHash is the keccak256 hash of the contract code (if any)
	GetCodeHash() common.Hash
	// SetCodeHash sets the code hash to the account fields
	SetCodeHash(code common.Hash) error
	// Type returns the type of Ethereum Account (EOA or Contract)
	Type() int8
}

For more information on Ethereum accounts head over to the x/evm module.

Addresses and Public Keys

BIP-0173 defines a new format for segregated witness output addresses that contains a human-readable part that identifies the Bech32 usage. Slinky uses the following HRP (human readable prefix) as the base HRP:

Network	Mainnet	Testnet
Slinky	slinky	slinky

There are 3 main types of HRP for the Addresses/PubKeys available by default on Slinky:

• 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	slinky	slinkypub	eth_secp256k1	20	33 (compressed)
Validator Operator	slinkyvaloper	slinkyvaloperpub	eth_secp256k1	20	33 (compressed)
Consensus Nodes	slinkyvalcons	slinkyvalconspub	ed25519	20	32

Address formats for clients

EthAccount can be represented in both Bech32 (slinky1...) and hex (0x...) formats 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): slinky1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw

• Address (EIP55 Hex): 0x91defC7fE5603DFA8CC9B655cF5772459BF10c6f

• Compressed Public Key: {"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"AsV5oddeB+hkByIJo/4lZiVUgXTzNfBPKC73cZ4K1YD2"}

Address conversion

The slinkyd debug addr <address> can be used to convert an address between hex and bech32 formats. For example:

 $ slinkyd debug addr slinky1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw
  Address: [20 87 74 109 255 45 223 158 7 130 139 67 69 211 4 9 25 175 86 82]
  Address (hex): 14574A6DFF2DDF9E07828B4345D3040919AF5652
  Bech32 Acc: slinky1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw
  Bech32 Val: slinkyvaloper1z3t55m0l9h0eupuz3dp5t5cypyv674jjn4d6nn

 $ slinkyd debug addr 14574A6DFF2DDF9E07828B4345D3040919AF5652
  Address: [20 87 74 109 255 45 223 158 7 130 139 67 69 211 4 9 25 175 86 82]
  Address (hex): 14574A6DFF2DDF9E07828B4345D3040919AF5652
  Bech32 Acc: slinky1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw
  Bech32 Val: slinkyvaloper1z3t55m0l9h0eupuz3dp5t5cypyv674jjn4d6nn

Key output

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

We can use the keys show command of slinkyd with the flag --bech <type> (acc|val|cons) to obtain the addresses and keys as mentioned above,

 $ slinkyd keys show dev0 --bech acc
- name: dev0
  type: local
  address: slinky1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw
  pubkey: '{"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"AsV5oddeB+hkByIJo/4lZiVUgXTzNfBPKC73cZ4K1YD2"}'
  mnemonic: ""

 $ slinkyd keys show dev0 --bech val
- name: dev0
  type: local
  address: slinkyvaloper1z3t55m0l9h0eupuz3dp5t5cypyv674jjn4d6nn
  pubkey: '{"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"AsV5oddeB+hkByIJo/4lZiVUgXTzNfBPKC73cZ4K1YD2"}'
  mnemonic: ""

 $ slinkyd keys show dev0 --bech cons
- name: dev0
  type: local
  address: slinkyvalcons1rllqa5d97n6zyjhy6cnscc7zu30zjn3f7wyj2n
  pubkey: '{"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"A/fVLgIqiLykFQxum96JkSOoTemrXD0tFaFQ1B0cpB2c"}'
  mnemonic: ""

Querying an Account

You can query an account address using the CLI, gRPC or

Command Line Interface

# NOTE: the --output (-o) flag will define the output format in JSON or YAML (text)
slinkyd q auth account $(slinkyd keys show dev0 -a) -o text

'@type': /ethermint.types.v1.EthAccount
base_account:
account_number: "0"
address: slinky1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw
pub_key:
  '@type': /ethermint.crypto.v1.ethsecp256k1.PubKey
  key: AsV5oddeB+hkByIJo/4lZiVUgXTzNfBPKC73cZ4K1YD2
sequence: "1"
code_hash: 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470

Cosmos gRPC and REST

# GET /cosmos/auth/v1beta1/accounts/{address}
curl -X GET "http://localhost:10337/cosmos/auth/v1beta1/accounts/slinky14au322k9munkmx5wrchz9q30juf5wjgz2cfqku" -H "accept: application/json"

JSON-RPC

To retrieve the Ethereum hex address using Web3, use the JSON-RPC eth_accounts or personal_listAccounts endpoints:

# 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:8545

curl -X POST --data '{"jsonrpc":"2.0","method":"personal_listAccounts","params":[],"id":1}' -H "Content-Type: application/json" http://localhost:8545