Application layer security design, implementation, vulnerability assessments and concerns, as opposed to infrastructure (e.g., ACLs on routers, IDSes, etc.)
application-security encompasses measures taken throughout the code's life-cycle to prevent gaps in the security policy of an application or the underlying system (vulnerabilities) through flaws in the design, development, deployment, upgrade, or maintenance or database of the application.
as stated in Wikipedia.
Since this tag is used in its general meaning, you are strongly encouraged to use one or more additional tags to better describe your specific case.
