/usr/bin/security A simple command line interface which lets you administer keychains, manipulate keys and certificates, and do just about anything the Security framework is capable of from the command line. By default security will execute the command supplied and report if anything went wrong.
/System/Library/Frameworks/Security.framework/Versions/A/Security Use the Security framework to protect information, establish trust, and control access to software. Broadly, security services support these goals: establish a user's identity (authentication) and then selectively grant access to resources (authorization); secure data, both on disk and in motion across a network connection; ensure the validity of code to be executed for a particular purpose.