Mobile Platform Development

We are in a need of an unified communication iOS and Android app whereby the users can communicate using WebRTC communication. Note: - We are not allowed to use third-party libraries! - Do not use third-party libraries! You must include everything inside the app. - The app may be used in a closed VPN infrastructure, accessible only when a closed VPN connection is made. The app architecture must allow the option to connect to a certain platform, it will make use of the database per platform, and it will make use of its own app database. It must be possible for the user to switch between platforms. For example when a user has both an account to the name of the company, it must be possible for the user to switch between the accounts rapidly. The switching allows the user to logout and login rapidly between platforms, without again using the manual login. The app must always encrypt all credentials of the user in the database, and when saving the credentials of the login / database the credentials must be stored in the keychain. - Security documentation Ensure you documentate the locations of where you have the cryptography integrated, and how it is integrated. Make sure all security settings and security integrations are documented very detailed. - Communication security Use for chat communication the Double Ratchet cryptography protocol in combination with Diffie-Hellman, but must be with Double Ratchet! The APP should contain the following functions to operate correctly as a communication APP. This will be discussed separately.