One of the main objectives of information security is to protect the confidentiality of data. In a web application, the goal is to ensure that the data exchanged between the user and the application is secure and hidden from any third party. When stored on the server, the data also needs to be secured from hackers. Cryptography, the practice of communicating through and deciphering secret writings or messages, is used to protect the confidentiality as well as the integrity of the data.
Current standard cryptographic algorithms have been designed, tested, and corrected at length by highly specialized teams of mathematicians and computer scientists. Examining their work in depth is beyond the scope of this book; also, trying to find vulnerabilities inherent in these algorithms is not the goal of this book. Instead...
