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np1sec challenge

The challenge involve partially implementing some of our XMPP test client event handlers for namely join, receive and send. The result will be a client that people can use to join and chat securely. Note that the purpose of the challenge is for the EQ team to get to know the candidates and be comfortable with their C++ competence before commencing our interview process. Please reach out if you get stuck somewhere – this is not considered against you.

Step 1: Get the code and get it compiled:

You need our fork of libgrypt for it:

https://github.com/equalitie/libgcrypt

Then you need to get the code

https://github.com/equalitie/np1sec

and follow the README. Finally test with the mock client:

./libnp1sec_test

If you link to original libgcrypt you’ll get some kind of grypt related
error.

Step 2: Run the xmpp test client. It is implemented in

https://github.com/equalitie/np1sec/blob/master/test/xmpp_test.cpp

Login to two different accounts. try
to chat, etc.
Step 3: Implement the join/send and receive handler

Look at the example at:
https://github.com/equalitie/np1sec/blob/master/test/chat_mocker_np1sec_plugin.cc#L54

and

https://github.com/equalitie/np1sec/blob/master/test/chat_mocker_np1sec_plugin.cc#L127

Notes that in case of mock client join and receive handler both are being handled by chat_mocker_np1sec_plugin_receive_handler but it happens in different function in case of libpurple.

Step 4: Implement the call backs:

You need to give some call backs to np1sec library. You can find the
association in case of chat mocker here:

https://github.com/equalitie/np1sec/blob/master/test/session_test.cc#L62

mockops->send_bare = send_bare;
mockops->join = new_session_announce;
mockops->leave = new_session_announce;
mockops->display_message = display_message;
mockops->set_timer = set_timer;
mockops->axe_timer = axe_timer;
They are implemented here:

https://github.com/equalitie/np1sec/blob/master/test/chat_mocker_np1sec_plugin.cc#L135

You only need to implement send_bare and send a do nothing functions for set_timer/axe_timer.

Step 5: Test your client:

Follow the lines in

https://github.com/equalitie/np1sec/blob/master/test/session_test.cc#L189

to initiate the np1sec UserState and see if you can join and talk to yourself.

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