message: Refactor signing strategy
diff: @@ -12,8 +12,7 @@ import express from 'express'
  import morgan from 'morgan'
  import { Stream } from 'stream'
  import { utils, Wallet } from 'ethers'
  -import { signChannelMessage } from '@connext/crypto'
  -import { toBN } from '@connext/utils'
  +import { toBN, ChannelSigner } from '@connext/utils'
  const delay = (time: number) => new Promise(res => setTimeout(res, time))
  @@ -107,6 +106,7 @@ export default {
  logger.info(`xpub: ${client.publicIdentifier}`)
  const wallet = Wallet.fromMnemonic(argv.mnemonic)
  + const signer = new ChannelSigner(wallet.privateKey, argv.ethereum)
  // // Handle incoming payments
  client.on(
  @@ -116,15 +116,22 @@ export default {
  let formattedAmount = formatEther(amount)
  logger.info(
  - `Received payment ${eventData.paymentId} (${formattedAmount} ETH) from ${eventData.sender}, unlocking with key from ${wallet.address}...`,
  + `Received payment ${eventData.paymentId} (${formattedAmount} ETH) from ${eventData.sender}, signer is ${eventData.transferMeta.signer}...`,
  )
  + if (signer.address !== eventData.transferMeta.signer) {
  + logger.error(
  + `Transfer's specified signer ${eventData.transferMeta.signer} does not match our signer ${signer.address}`,
  + )
  + return
  + }
  +
  const mockAttestation = hexlify(randomBytes(32))
  const digest = solidityKeccak256(
  ['bytes32', 'bytes32'],
  [mockAttestation, eventData.paymentId],
  )
  - const signature = await signChannelMessage(wallet.privateKey, digest)
  + const signature = await signer.signMessage(digest)
  await client.resolveCondition({
  conditionType: ConditionalTransferTypes.SignedTransfer,
  paymentId: eventData.paymentId,
  