currently it is not open source, an LEMP stack, also a MVP and looking for improvement.

The next iteration will turn it into a truly 1-time use fully encrypted inbox, implementing a PGP with end to end encryption in next iteration. The public key will store in our database, will be used to sign message before send to our server. The private PGP key is expected to store as a AES-CBC-128 format by your 8 digits pin (or if you want longer) and the 8 digits pin will be hashed before send to our database.

The next iteration proposed design is supposed to be fully encrypted.