NSA (Short for National Security Agency) is responsible for handling Computer Security Certification.
A firewall is a security mechanism, which prevents unauthorized access to a network or a resource on a network. A firewall is a networking device, either hardware or software based, that controls access to your organization's network. This controlled access is designed to protect data and resources from an outside threat. To do this, firewalls typically are placed at a network's entry/exit points - for example, between an internal network and the Internet. After it is in place, a firewall can control access into and out of that point.
A key fob is a small, programmable hardware device that provides the key fob holder with access to a physical object such as a computer, storage media, or a networking equipment. Some types of key fobs require physical contact to grant access to the object in question, while other types of key fob can grant access wirelessly. A key fob may also be referred to as a hardware token or security token.
Access cards can serve the dual purpose as an Identification card or badge to employees, allowing them easy access to the building without compromising security. The magnetic strip on the card carries a specific code that unlocks the system when the card is swiped through the system.
Biometrics is to do with finger print or retina scan. It also serves the same purpose as that of access card, but relies on an employees biometrics to provide access to a building or a resource.
Lock and key is the traditional method of physically securing a building or a cabinet. This is increasingly being replaced by electronic means these days.
Identification badges are used to provide proof of access to others. Proper processes and procedures must be in place for a successful implementation of this prevention tactic. badges are only as good as the enforcement of the badges themselves. In many organizations that implement ID badges, all employees are required to display their ID badge at all times.