anchor.diff:             token = encrypt(T)}.
   
   encrypt(PlainText) ->
  -    X = get(left),
  +    X = get_key(),
       State = crypto:stream_init(aes_ctr, X, X),
       {_, CipherText} = crypto:stream_encrypt(State, PlainText),
       CipherText.
   
   
   decrypt(CipherText) ->
  -    X = get(left),
  +    X = get_key(),
       State = crypto:stream_init(aes_ctr, X, X),
       {_, PlainText} = crypto:stream_decrypt(State, CipherText),
       PlainText.
  +
  +get_key() ->
  +    case application:get_env(nook, left) of
  +        undefined ->
  +            Key = uuid:get_v4(),
  +            application:put_env(nook, left, Key),
  +            Key;
  +        Value ->
  +            Value
  +end.
  
positive.code:             refresh_credentials()
      end.
  
  
  refresh_credentials() ->
      {ok, IamEp} = application:get_env(nook, metadata),
      case httpc:request(IamEp ++ "NookRole") of
  
negative.code: 
  
  init([]) ->
      SupFlags = #{strategy => one_for_one,
                   intensity => 60,
                   period => 300},
  