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Prerequisite Readings​

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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 the Cosmos Hub, 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 an mnemonic phrase on a blockchain, it is therefore important to use that blockchain’s specific derivation path.

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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. cosmos1...). 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.

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EVM Accounts​

Cosmos EVM 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 EVM-based accounts is m/44'/60'/0'/0. It is recommended to use 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 Cosmos EVM 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 accounttype 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.

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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. There are 3 main types of HRP for the Addresses/PubKeys available by default on the Cosmos EVM:
  • 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 PrefixPubkey bech32 PrefixCurveAddress byte lengthPubkey byte length
Accountscosmoscosmospubeth_secp256k12033 (compressed)
Validator Operatorcosmosvalopercosmosvaloperpubeth_secp256k12033 (compressed)
Consensus Nodescosmosvalconscosmosvalconspubed255192032

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Address formats for clients​

EthAccount can be represented in both Bech32 (e.g. cosmos1...) 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): cosmos1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw
  • Address (EIP55 Hex): 0x91defC7fE5603DFA8CC9B655cF5772459BF10c6f
  • Compressed Public Key: {"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"AsV5oddeB+hkByIJo/4lZiVUgXTzNfBPKC73cZ4K1YD2"}

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Address conversion​

The appd debug addr <address> can be used to convert an address between hex and bech32 formats. For example: Bech32 
 $ appd debug addr cosmos1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw  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: cosmos1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw  Bech32 Val: cosmosvaloper1z3t55m0l9h0eupuz3dp5t5cypyv674jjn4d6nn
Hex 
 $ cosmosd 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: cosmos1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw  Bech32 Val: cosmosvaloper1z3t55m0l9h0eupuz3dp5t5cypyv674jjn4d6nn

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Key output​

The Cosmos SDK Keyring output (i.e appd keys) only supports addresses and public keys in Bech32 format.
We can use the keys show command of appd with the flag --bech <type> (acc|val|cons) to obtain the addresses and keys as mentioned above, Accounts 
 $ appd keys show dev0 --bech acc- name: dev0  type: local  address: cosmos1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jw  pubkey: '{"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"AsV5oddeB+hkByIJo/4lZiVUgXTzNfBPKC73cZ4K1YD2"}'  mnemonic: ""
Validator 
 $ appd keys show dev0 --bech val- name: dev0  type: local  address: cosmosvaloper1z3t55m0l9h0eupuz3dp5t5cypyv674jjn4d6nn  pubkey: '{"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"AsV5oddeB+hkByIJo/4lZiVUgXTzNfBPKC73cZ4K1YD2"}'  mnemonic: ""
Consensus 
 $ appd keys show dev0 --bech cons- name: dev0  type: local  address: cosmosvalcons1rllqa5d97n6zyjhy6cnscc7zu30zjn3f7wyj2n  pubkey: '{"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"A/fVLgIqiLykFQxum96JkSOoTemrXD0tFaFQ1B0cpB2c"}'  mnemonic: ""

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Querying an Account​

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

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Command Line Interface​

# NOTE: the --output (-o) flag will define the output format in JSON or YAML (text)appd q auth account $(appd keys show dev0 -a) -o text'@type': /ethermint.types.v1.EthAccountbase_account:account_number: "0"address: cosmos1z3t55m0l9h0eupuz3dp5t5cypyv674jj7mz2jwpub_key:  '@type': /ethermint.crypto.v1.ethsecp256k1.PubKey  key: AsV5oddeB+hkByIJo/4lZiVUgXTzNfBPKC73cZ4K1YD2sequence: "1"code_hash: 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470

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Cosmos gRPC and REST​

# GET /cosmos/auth/v1beta1/accounts/{address}curl -X GET "http://localhost:10337/cosmos/auth/v1beta1/accounts/cosmos14au322k9munkmx5wrchz9q30juf5wjgz2cfqku" -H "accept: application/json"

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JSON-RPC​

To retrieve the Ethereum hex address using Web3, use the JSON-RPC eth_accounts or personal_listAccounts endpoints: 
# query against a local nodecurl -X POST --data '{"jsonrpc":"2.0","method":"eth_accounts","params":[],"id":1}' -H "Content-Type: application/json" http://localhost:8545curl -X POST --data '{"jsonrpc":"2.0","method":"personal_listAccounts","params":[],"id":1}' -H "Content-Type: application/json" http://localhost:8545