In software engineering, a functional requirement defines a function of a software system or its component. A function is described as a set of inputs, the behavior, and outputs. Functional requirements may be calculations, technical details, data manipulation and processing and other specific functionality that define what a system is supposed to accomplish. Behavioral requirements describing all the cases where the system uses the functional requirements are captured in use cases.
Here, the system has to perform the following tasks:
• Take userid and password along with secret key, match it with corresponding database entries. If a match is found then continue else raise an error message.
• Encrypt the file to form a new encrypted file by using an encryption algorithm.
• Must be able to retrieve the original file from the encrypted file using the corresponding decryption algorithm.
• If any modification is performed on encrypted file, owner of the file should be notified.