For anyone looking for reference.

I did NOT POST API successfully. (2020/10)
I believe I created a CORRECT RFC6238 token
- I was able to generate exactly same "Table 1: TOTP Table" TOTP token.

But, I still got Access denied: Invalid token, wrong code.

maybe I am wrong, and I give up to submit my demo.
- (I start to think maybe, this is not my problem.)
hope someone POST successfully, and prove me wrong.

You can find some ppl asking or public their code on github

google some key word
github search key word

And I think glassdoor is also worth to read (not relate this challenge)

https://www.glassdoor.com/Interview/HENNGE-Interview-Questions-E1276040.htm
(Use browser's private mode to pretend first time visitor.)

About secrets

If you read the RFC6238 document. The doc say

The test token shared secret uses the ASCII string value "12345678901234567890".

A lot of ppl confusing:

What is 12345678901234567890, and
Why using seed64 in the document's sample code ?

String seed64 = "3132333435363738393031323334353637383930" +
         "3132333435363738393031323334353637383930" +
         "3132333435363738393031323334353637383930" +
         "31323334";

12345678901234567890 is (token shared) secret, just a random string.
3132333435363738393031323334353637383930 is 12345678901234567890's ASCII HEX encoded
for HMAC-SHA512, we need 64 bytes seed. Just repeat the string, then we got seed64
- (hex encode: Encode each byte as two hexadecimal characters.)

// nodejs
Buffer("12345678901234567890", 'ascii').toString('hex')
// 3132333435363738393031323334353637383930

If you are using 3rd parity library

I think library will do the ASCII hex encode for you.
You can use 12345678901234567890 as secret to test, to generate same "Table 1: TOTP Table"'s result.
- "Table 1: TOTP Table"'s first col "Time (sec)" is "Unix epoch". when you setting lib's config, maybe is "UNIX time * 1000", e.x: "59 * 1000" (depend on your language or library.)
read your 3rd parity library's test and source code may help you more understand that library.

Jacky's HENNGE Admission Challenge 003 (unsubmitted)

about this demo

framework: react (create-react-app)
style engine: css-in-js (styled-components)
others
- storybook for UI component develop

Clone and Install

git clone https://github.com/flameddd/hennge_challenge
cd hennge_challenge
npm install
npm start

then visit http://localhost:3000/

Date Set

dataset.js
email date range from 2019/12/31 0:30 to 2020/1/3 0:20
filter Out of above date range to see Empty Result page.

Folder structure and File

\---src
  |   App.js            // App Entry, Layout
  |   colors.js         // define color palette
  |   constants.js      // define constant, enums
  |   dataset.js        // fake data set for demo 
  |   
  +---assets            // image asset from "frontend_resources.zip" 
  +---Components        // UI components
  |     EmptyResult.js
  |     ExtendMail.js
  |     Normalize.js
  |     ResultTitle.js
  |     DatePicker.js
  |     Table.js
  | 
  \---utils           // utility function
\---screenshots       // image for README, REPORT and IMPROVEMENTS present

Screenshots


desktop


hover


mail extended


mail extended


date picker


result 0


mobile	scroll	mail extended


mail extended	date picker	result 0