DACS is primarily used with Apache web servers to provide enhanced access control for web pages, CGI programs and servlets, and other web-based assets, and to federate Apache servers.
Released under an open-source license, DACS provides a modular authentication framework that supports an array of common authentication methods and a rule-based authorization engine that can grant or deny access to resources, named by URLs, based on the identity of the requestor and other contextual information.
In addition to simple web-based APIs, command-line interfaces are also provided to much of the functionality.
The DACS distribution includes various cryptographic functionality, such as message digests, HMACs, symmetric and public key encryption, ciphers (ChaCha20, OpenSSL), digital signatures, password-based key derivation functions (HKDF, PBKDF2), and memory-hard key derivation functions (scrypt, Argon2), much of which is available from a simple scripting language.
Expressed as a set of XML documents, the rules are consulted at run-time to determine whether access to a given resource should be granted or denied.