Sanctum Inc. was a Santa Clara, California-based information technology company focused on application security.

Sanctum offered a firewall, AppShield, and scanner, AppScan, for application-layer security for Web environments.

[3] The company has done an extensive research in application security and applying formal methods to real life software[4] in collaboration with Turing Award winner Professor Amir Penueli.

[9] AppShield worked by inspecting incoming HTTP requests and blocking malicious attacks based on a dynamic policy which was composed by analyzing the outgoing HTML pages.

[14] In June 2000 the company introduced AppScan the world's first Web Security Vulnerability Assessment solution.