A means of controlling access by users to computer systems or to data on a computer system. Different types of access exist. For example, “read access” would suggest that the user has authorization only to read the information he or she is accessing, whereas “write access” would suggest that the user has authorization to both read and alter accessed data.
Access control is also an important concept within Web and other applications. The segmentation of functionality, and even entire sections of an application, are based on access control.