https://hackernoon.com/mobile-api-security-techniques-682a5da4fe10
https://stackoverflow.com/questions/12712260/storing-authentication-token-on-ios
https://stackoverflow.com/questions/46494476/best-practices-for-storing-a-token-in-ios-app
https://medium.freecodecamp.org/how-to-make-authentication-easier-with-json-web-token-cc15df3f2228