code: func StoreKey(dir, auth string, scryptN, scryptP int) (common.Address, error) {
  	_, a, err := storeNewKey(&keyStorePassphrase{dir, scryptN, scryptP, false}, rand.Reader, auth)
  	return a.Address, err
  }
docs: // StoreKey generates a key, encrypts with 'auth' and stores in the given directory