HaLo chip

An easy to use javascript library for interacting with HaLo chips

Installation

npm i halo-chip

Usage

import { listKeys, ethSignMessage } from `halo-chip`

const keys = await listKeys()
console.log('keys:')
keys.map(k => console.log)
const address = keys[0].address

const signature = await ethSignMessage('test123', 1, address)
console.log('signature:', signature)

Usage with Ceramic

import { DIDSession } from 'did-session'
import { EthereumWebAuth, getAccountId } from '@didtools/pkh-ethereum'

const keys = await listKeys()
const { address, slot } = keys[0]
const accountId = { address: address.toLowerCase(), chainId: { reference: 1, namespace: 'eip155' } }
  
const authMethod = await EthereumWebAuth.getAuthMethod({
  request: async ({ method, params }) => ethSignMessage(params[0], slot, params[1])
}, accountId)
const session = await DIDSession.authorize(authMethod, { resources: ['ceramic://*?model=kjz...'] })

Parse url params

import { parseURLParams } from `halo-chip`
const params = `?v=c3&static=4104FAC52DEA1D02FC0F1473B832B88F15DC9CEFBFEE690C3C9B8FECF8045B2A06166119F5C539E9FF418A58DA95ED057DB17E76E9B57531025BEFE4B45EB0DF07634104422738D17192382F19482649E07022615930C3C1CB29A51CFE23D62445CDB8729A40DE69A79697F3704C7D684365846CF6DB974E33E47998BDB2DAB1131D330E000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000&latch1=E5D961F8DAD5F030F57E88E72AAD26492D722AFB5CC84256DCA2BA6362BEBF51&latch2=0000000000000000000000000000000000000000000000000000000000000000&cmd=81020000001B8F48E0B1A3B19C5DF8D763717A7BE27475FA6AF0E34F8449704C3A8B00&res=3046022100D5871CDE09C5AB891F4D023EC278DF8F1CE5B6970F478C825D812C946F15593B022100EA326B2683E212F34CF87C051CF0BA00BCD1530B72FE8D8754584F480C38ED3400000000`
const parsed = parseURLParams(params)
console.log(parsed)

API

listkeys() ⇒ keys

List the keys of the device

Returns

• object[] - The list of keys
  • object[].key - The public key
  • object[].slot - Slot number of the key
  • object[].address - Ethereum address of the key
  • object[].did - PKH DID of the key

ethSignMessage(message, slot, address) ⇒ signature

Sign a message using EIP191.

Params

• message: string - The message to sign
• slot: number - The slot index of the key to use
• address: string - The the ethereum address of the key used

Returns

• string - The signature encoded as a hex string

ethSignHash(hash, slot, address) ⇒ signature

Sign a hash and return a recoverable signature.

Params

• hash: string - The hex encoded hash to sign
• slot: number - The slot index of the key to use
• address: string - The the ethereum address of the key used

Returns

• string - The signature encoded as a hex string

sign(hash, slot) ⇒ signature

Sign a hash

Params

• hash: string - The hex encoded hash to sign
• slot: number - The slot index of the key to use

Returns

• object - The signature
  • object.r - The r value encoded as hex
  • object.s - The s value encoded as hex

parseURLParams(params) => parsed

Parse the url parameters generated when scanning a HaLo chip.

Params

• params: string - The query params to parse

Returns

• object - The parsed values
  • object.tagVersion - The version of the scanned chip
  • object.keys[] - The list of the keys
    • object.keys[].key - The public key
    • object.keys[].slot - Slot number of the key
    • object.keys[].address - Ethereum address of the key
    • object.keys[].did - PKH DID of the key
  • object.proof - The proof generated by the chip
    • object.proof.challenge - The 32 byte value signed in the proof (counter + random value)
    • object.proof.signature - The signature produced by the key at slot 2
    • object.proof.counter - The current value of the counter
  • object.storage[] - The list of values in the device storage
    • object.keys[].value - The value of this storage slot
    • object.keys[].slot - Slot number of this storage slot

generateKey() ⇒ void

Generate the 3rd key of the Halo chip.

writeStorage(slot, data) ⇒ void

Write a 32 bytes to the latch storage.

Warning: Write operation is permanent. It's not possible to remove or update the value afterwards.

Params

• slot: number - The slot index of the key to use
• data: string - The 32 bytes encoded as a hex string

readStorage(slot) ⇒ data

Read the 32 bytes from the latch storage.

Params

• slot: number - The slot index of the key to use

Returns

• string - The data in the storage slot

License

MIT