The present invention concerns methods and apparatus for implementing context-dependent security for files and other computer system resources. In particular, methods and apparatus of the present invention implement context-based permissions that are used in context-dependent file security. In examples of the present invention, the context-based permissions may allow access to a file only when an attempt to access the file is made at a certain time of day, or from an authorized computer system, or from a computer having a certain application program installed. In general terms, the context-based permissions may specify time, location and application information that either alone or in combination may be used to restrict access to a file.