HAVAH (HVH)

Sign HAVAH transactions. HAVAH is an ICON-family chain, so transactions use the ICON-native wire shape (from/to/value/stepLimit/nid/nonce). The bridge converts this wire into a HavahTransaction before the device signs.

Field	Value
coinType	858
keyPath	m/44'/858'/<accountIdx>'/0/0
amount unit	loop
chainId	havah:mainnet/slip44:858

Supported Methods

Method	Supported
getAddress	✓
signTransaction	✓
signMessage	✗
signTypedData	✗
signAuthEntry	✗

Requirements

Minimum firmware for each method. The two models are on different version lines, so DCENT Biometric Wallet and DCENT X are listed separately (the numbers are not comparable across models). Below this the request returns the firmware-update error (5005) and the bridge prompts to update.

Method	DCENT Biometric Wallet	DCENT X
getAddress	2.26.0 or higher	1.0.0 or higher
signTransaction	2.26.0 or higher	1.0.0 or higher

getAddress — account address

Retrieves the HAVAH account address for a chainId + keyPath. HAVAH uses the ICON-family hx… address format (there are no address variants). Call this before building a transaction so from matches the device account.

Field	Type	Required	Source	Description
chainId	string	Required	App	Full CAIP-19 id — havah:mainnet/slip44:858
keyPath	string	Required	App	BIP-44 derivation path — default m/44'/858'/0'/0/0

Request

await dcent.getAddress({
  chainId: 'havah:mainnet/slip44:858',
  keyPath: "m/44'/858'/0'/0/0"
})

Response

Field	Type	Description
header.status	string	success on a completed request
body.command	string	Echoes the method — getAddress
body.parameter.address	string	HAVAH account address in ICON-family hx… format

{
  "header": {
    "version": "1.0",
    "status": "success"
  },
  "body": {
    "command": "getAddress",
    "parameter": {
      "address": "hx…"
    }
  }
}

signTransaction — ICON-native wire

Variant — native HVH transfer

payload.transaction:

{
  "from": "hx0000000000000000000000000000000000000000",
  "to": "hx0000000000000000000000000000000000000000",
  "value": "0xDE0B6B3A7640001",
  "stepLimit": "0x186a0",
  "stepPrice": "0x2e90edd000",
  "timestamp": "0x0",
  "nid": "0x100",
  "nonce": "0x1",
  "version": "0x3"
}

Field	Type	Required	Source	Description
from	string	Required-Real	Wallet	Device HAVAH account (hx…)
to	string	Required-Real	App	Recipient (hx… for native send)
value	hex	Required	App	Amount in loop, 0x-prefixed hex (1 HVH = 1e18 loop). Keep as hex — values exceed MAX_SAFE_INTEGER
stepLimit	hex	Required	App	Step (gas) limit, hex. When provided together with stepPrice the bridge builds a self-contained preparedFee
stepPrice	hex	Required-Real	App	Real, current step price, hex — the app must supply it; a stale/zero value is rejected
timestamp	hex	Required-Real	App	ICON microsecond epoch. The wallet never fills this in — the value you send is the one that is signed. Omitting it fails with -32602
nid	hex	Required	App	Network id — 0x100 for mainnet
nonce	hex	Optional	App	Transaction nonce, hex
version	hex	Required	App	ICON tx version — 0x3

js — Request:

await dcent.sign({
  method: 'signTransaction',
  chainId: 'havah:mainnet/slip44:858',
  payload: {
    keyPath: "m/44'/858'/0'/0/0",
    transaction: {
      from: "hx0000000000000000000000000000000000000000",
      to: "hx0000000000000000000000000000000000000000",
      value: "0xDE0B6B3A7640001",
      stepLimit: "0x186a0",
      stepPrice: "0x2e90edd000",
      timestamp: "0x0",
      nid: "0x100",
      nonce: "0x1",
      version: "0x3"
    }
  }
})  // → body.parameter.signature

Response

Field	Type	Description
header.status	string	success on a completed signature
body.command	string	Signing command echo — signTransaction
body.parameter.signature	string	Broadcast-ready serialized signed HAVAH (ICON) transaction, not a bare r/s/v signature. Submit it as-is to a HAVAH node

{
  "header": {
    "status": "success"
  },
  "body": {
    "command": "signTransaction",
    "parameter": {
      "signature": "0x…"
    }
  }
}

Variant — HSP-20 token transfer

info

Token model: form-D descriptor. Always send the token's symbol and decimals under transaction.token — the bridge signs with no network access and uses the decimals you supply directly, so the device shows the correct token name and amount. See Core Concepts → Token descriptors.

HSP-20 (IRC-2-like) tokens use the ICON call data shape. to is the token contract (cx…), the real recipient is data.params._to, and native value stays 0x0 (no native HVH moves).

payload.transaction:

{
  "dataType": "call",
  "from": "hx0000000000000000000000000000000000000000",
  "to": "cxd7fed2ae1d9b2314087520efe1870c33e5c5baa4",
  "value": "0x0",
  "stepLimit": "0x186a0",
  "stepPrice": "0x2e90edd000",
  "timestamp": "0x0",
  "nid": "0x100",
  "nonce": "0x1",
  "version": "0x3",
  "data": {
    "method": "transfer",
    "params": {
      "_to": "hx0000000000000000000000000000000000000000",
      "_value": "0xDE0B6B3A7640001"
    }
  }
}

Field	Type	Required	Source	Description
dataType	enum	Required	App	Must be call for a contract call
to	string	Required-Real	App	Token contract address (cx…), not the recipient
value	hex	Required	App	Native HVH amount — keep 0x0 for a token-only transfer
data.method	string	Required	App	Contract method — transfer
data.params._to	string	Required-Real	App	Real token recipient (hx…)
data.params._value	hex	Required	App	Token amount in base units, 0x-prefixed hex (PER has 18 decimals; 0xF4240 = 1e6 for a 6-decimal token)
timestamp	hex	Required-Real	App	ICON microsecond epoch — the wire path never fills it in; omitting it fails with -32602

js — Request:

await dcent.sign({
  method: 'signTransaction',
  chainId: 'havah:mainnet/slip44:858',
  payload: {
    keyPath: "m/44'/858'/0'/0/0",
    transaction: {
      dataType: "call",
      from: "hx0000000000000000000000000000000000000000",
      to: "cxd7fed2ae1d9b2314087520efe1870c33e5c5baa4",
      value: "0x0",
      stepLimit: "0x186a0",
      stepPrice: "0x2e90edd000",
      timestamp: "0x0",
      nid: "0x100",
      nonce: "0x1",
      version: "0x3",
      data: { method: "transfer",
        params: { _to: "hx0000000000000000000000000000000000000000",
                  _value: "0xDE0B6B3A7640001" } }
    }
  }
})  // → body.parameter.signature

Response

Field	Type	Description
header.status	string	success on a completed signature
body.command	string	Signing command echo — signTransaction
body.parameter.signature	string	Broadcast-ready serialized signed HAVAH (ICON) transaction carrying the HSP-20 call data, not a bare r/s/v signature. Submit it as-is to a HAVAH node

{
  "header": {
    "status": "success"
  },
  "body": {
    "command": "signTransaction",
    "parameter": {
      "signature": "0x…"
    }
  }
}

info

HSP-20 tokens are signed under parent HAVAH on mainnet (slip44:858). A wrong chain is rejected (-32602); any HSP-20 contract signs — supply a form-D descriptor (see Core Concepts → Token descriptors) to prevent a silent native HVH transfer.

Variant — HSP-20 form-D descriptor

Send a compact token descriptor instead of a full ICON dataType:"call" envelope. The bridge builds the transfer(_to,_value) SCORE call from { contract, to, amount }, rewrites to to the contract address, and sets value to 0x0. Envelope fields you send (from, stepLimit, stepPrice, nid, nonce, version) are preserved. amount is a base-unit string (not rescaled by decimals).

payload.transaction:

{
  "token": {
    "contract": "cxd8303731bf989a1597a6d38505d7a9483c4d9a38",
    "to": "hx0000000000000000000000000000000000000000",
    "amount": "1000000",
    "decimals": 6,
    "symbol": "GODH"
  },
  "from": "hx0000000000000000000000000000000000000000",
  "stepLimit": "0x186a0",
  "stepPrice": "0x2e90edd000",
  "timestamp": "0x0",
  "nid": "0x100",
  "nonce": "0x1",
  "version": "0x3"
}

Field	Type	Required	Notes
token.contract	string	Required	SCORE address; must match cx + 40 hex chars. Unregistered tokens allowed.
token.to	string	Required	Recipient (hx…). Becomes data.params._to.
token.amount	string	Required	Base-unit integer string; not rescaled by decimals. 0 is allowed.
token.decimals	number	Required	Base-unit exponent; enables descriptor resolution on the device.
token.symbol	string	Optional	Display metadata only.
from	string	Required-Real	Device HAVAH account that signs (hx…). Omitting it fails with -32602.
stepLimit / stepPrice	string	Required	Map to the fee gate (gasLimit / fee). Zero or missing fails the gate.
nid / nonce / version	string	Optional	ICON envelope fields; passed through unchanged.
timestamp	hex	Required-Real	ICON microsecond epoch — the wire path never fills it in; omitting it fails with -32602

info

Verified on device (2026-07-20): this descriptor displays as GODH 1.0 — amount "1000000" at decimals 6. Replace token.to / from with your own device HAVAH account (hx…).

Common Mistakes

danger

Decimal amounts — value / _value must be 0x-prefixed hex loop, not a decimal string. Keep them as hex because values exceed MAX_SAFE_INTEGER. Token to vs recipient — for HSP-20, to is the contract (cx…) and the recipient is data.params._to (hx…). Putting the recipient in to moves native HVH instead. Non-zero value on a token transfer — leave value as 0x0 for HSP-20; a non-zero value sends native HVH alongside the token. Missing stepLimit — without it the bridge cannot build preparedFee. Missing stepPrice — the app must supply a real, current step price; it is not auto-filled.

• signTransaction
• getAddress
• Error Codes