Write an Android application -- 2

Mobile APP running platform is for Android and Apple. Developer will need to do all the missing portion in the backend integrated to the existing SIP registration server, and MySQL DB. Centos (Linux) knowledge is needed as all existing server is run on Centos OS. A secure data exchange between APP and the server is needed to be done and advise by the developer on how to get it done at employer equipment. Protocol such as https/TLS or whatever best industry practice can be recommended by the developer for this security on data exchange needed. Employer will support with mobile dialer’s SDK. All the work on the code plus the IDE setup for running the code will also need to setup at employer PC via remote access software. Developer can freely choice the IDE for the development as they wish but need to apply for Centos OS compilation environment. The SMS (two SMS service - mobile operator SMS service send to user mobile phone during user registration phase, and social media chat service in the APP) backend service is needed from developer. Employer will provide all necessary hardware for this two application. APP need to be able to apply notification push service from Google (Android) and Apple (iOS). NDA needed to be signed by developer after project is accepted the developer. All code developing in this project will belong to the employer.