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Heimdall’s auth module is responsible for specifying the base transaction and account types for an application. It contains the ante handler, where all basic transaction validity checks (signatures, nonces, auxiliary fields) are performed, and exposes the account keeper, which allows other modules to read, write, and modify accounts.

Gas and fees

Fees serve two purposes for an operator of the network.

  1. Fees limit the growth of the state stored by every full node and allow for general purpose censorship of transactions of little economic value. Fees are best suited as an anti-spam mechanism where validators are disinterested in the use of the network and identities of users.
  2. Since Heimdall doesn’t support custom contract or code for any transaction, it uses fixed cost transactions. For fixed cost transactions, the validator can top up their accounts on the Ethereum chain and get tokens on Heimdall using the Topup module.


Besides accounts (specified in State), the types exposed by the auth module are StdSignature, the combination of an optional public key and a cryptographic signature as a byte array, StdTx, a struct that implements the sdk.Tx interface using StdSignature, and StdSignDoc, a replay-prevention structure for StdTx which transaction senders must sign over.


A StdSignature is the types of a byte array.

// StdSignature represents a sig
type StdSignature []byte


StdTx is a struct that implements the sdk.Tx interface, and is likely to be generic enough to serve the purposes of many types of transactions.

type StdTx struct {
  Msg       sdk.Msg      `json:"msg" yaml:"msg"`
  Signature StdSignature `json:"signature" yaml:"signature"`
  Memo      string       `json:"memo" yaml:"memo"`


StdSignDoc is a replay-prevention structure to be signed over, which ensures that any submitted transaction (which is simply a signature over a particular byte string) will only be executable once on a Heimdall.

// StdSignDoc is replay-prevention structure.
// It includes the result of msg.GetSignBytes(),
// as well as the ChainID (prevent cross chain replay)
// and the Sequence numbers for each signature (prevent
// inchain replay and enforce tx ordering per account).
type StdSignDoc struct {
 ChainID       string          `json:"chain_id" yaml:"chain_id"`
 AccountNumber uint64          `json:"account_number" yaml:"account_number"`
 Sequence      uint64          `json:"sequence" yaml:"sequence"`
 Msg           json.RawMessage `json:"msg" yaml:"msg"`
 Memo          string          `json:"memo" yaml:"memo"`


It manages addresses, coins and nonce for transactions. It also signs and validates transactions.


type BaseAccount struct {
  Address types.HeimdallAddress `json:"address" yaml:"address"`
  Coins types.Coins `json:"coins" yaml:"coins"`
  PubKey crypto.PubKey `json:"public_key" yaml:"public_key"`
  AccountNumber uint64 `json:"account_number" yaml:"account_number"`
  Sequence uint64 `json:"sequence" yaml:"sequence"`


The auth module contains the following parameters:

Key Type Default value
MaxMemoCharacters uint64 256
TxSigLimit uint64 7
TxSizeCostPerByte uint64 10
SigVerifyCostED25519 uint64 590
SigVerifyCostSecp256k1 uint64 1000
DefaultMaxTxGas uint64 1000000
DefaultTxFees string “1000000000000000”

CLI commands

Show account

Use the following command to print account related data into Heimdall:

heimdalld show-account

Expected result:

 "address": "0x68243159a498cf20d945cf3E4250918278BA538E",
 "pub_key": "0x040a9f6879c7cdab7ecc67e157cda15e8b2ddbde107a04bc22d02f50032e393f6360a05e85c7c1ecd201ad30dfb886af12dd02b47e4463f6f0f6f94159dc9f10b8"

Account and coin details

To display account details, coins, sequence and account number:

heimdallcli query auth account 0x68243159a498cf20d945cf3E4250918278BA538E --trust-node

Expected result:

address: 0x68243159a498cf20d945cf3e4250918278ba538e
- denom: matic
    i: "1000000000000000000000"
pubkey: ""
accountnumber: 0
sequence: 0


Use the following command to print all params:

heimdallcli query auth params

Expected result:

max_memo_characters: 256
tx_sig_limit: 7
tx_size_cost_per_byte: 10
sig_verify_cost_ed25519: 590
sig_verify_cost_secp256k1: 1000
max_tx_gas: 1000000
tx_fees: "1000000000000000"


Name Endpoint Description
Account details /auth/accounts/{address} Returns all details for an address
Account sequence details /auth/accounts/{address}/sequence Returns only necessary details for signing
Auth params /auth/params Returns all params auth module uses