Send encrypted MAM_DATA to a service provider.

device-client.js

/**
  * Send encrypted MAM data to a service provider.
  *
  * @function sendMamData
  * @param {string} seed IOTA seed of sender
  * @param {string} address IOTA address of the service provider
  * @param {string} publicKey Public key of the service provider in trytes
  * @returns {Promise} containing IOTA transactions
  */
async sendMamData(seed, address, publicKey) {
  const { channel: { side_key, next_root } } = this.mam.getMamState();
  const mamData = {
    root: ntru.encrypt(next_root, publicKey),
    sideKey: ntru.encrypt(side_key, publicKey),
  };

  logger.info(`Provide service provider ${address} with MAM data ${JSON.stringify(mamData)}`);

  const message = { type: MAM_DATA_TYPE, root: this.root, mamData };
  return iota.send(seed, address, message);
}