MD5 Definition The MD5 hashing algorithm is a one-way cryptographic function that accepts a message of any length as input and returns as output a fixed-length digest value to be used for authenticating the original message. The MD5 hash function was originally designed for use as a secure cryptographic hash algorithm for authenticating digital signatures. MD5 has been deprecated for uses other than as a non-cryptographic checksum to verify data integrity and detect unintentional data corrup...

tunneling or port forwarding Tunneling, also known as "port forwarding," is the transmission of data intended for use only within a private, usually corporate network through a public network in such a way that the routing nodes in the public network are unaware that the transmission is part of a private network. Tunneling is generally done by encapsulating the private network data and protocol information within the public network transmission units so that the private network protocol inf...

Transport Layer Security (TLS) Definition Transport Layer Security (TLS) is a protocol that provides privacy and data integrity between two communicating applications. It's the most widely deployed security protocol used today, and is used for Web browsers and other applications that require data to be securely exchanged over a network, such as file transfers, VPN connections, instant messaging and voice over IP. TLS evolved from Netscape's Secure Sockets Layer (SSL) protocol and has largely...

Web Application Firewall (WAF) Definition A Web application firewall (WAF) is a firewall that monitors, filters or blocks data packets as they travel to and from a Web application. A WAF can be either network-based, host-based or cloud-based and is often deployed through a proxy and placed in front of one or more Web applications. Running as a network appliance, server plug-in or cloud service, the WAF inspects each packet and uses a rule base to analyze Layer 7 web application logic and filt...

Security as a Service (SaaS) Definition What is security-as-a-service (SaaS)? Security-as-a-service (SaaS) is an outsourcing model for security management. Typically, Security as a Service involves applications such as anti-virus software delivered over the Internet but the term can also refer to security management provided in-house by an external organization. Security-as-a-Service offers a number of benefits, including: Constant virus definition updates that are not reliant on use...

anonymous Web surfing (Web anonymizer, SafeWeb) Anonymous Web surfing allows a user to visit Web sites without allowing anyone to gather information about which sites the user visited. Services that provide anonymity disable pop-up windows and cookies and conceal the visitor's IP address. These services typically use a proxy server to process each HTTP request. When the user requests a Web page by clicking a hyperlink or typing a URL into their browser, the service retrieves and displays the in...

Firewall Definition A firewall is a network security system, either hardware- or software-based, that uses rules to control incoming and outgoing network traffic. A firewall acts as a barrier between a trusted network and and an untrusted network. A firewall controls access to the resources of a network through a positive control model. This means that the only traffic allowed onto the network is defined in the firewall policy; all other traffic is denied. History and types of firewal...

National Security Agency (NSA) The National Security Agency (NSA) is the official U.S. cryptologic (the science of cryptographic design and decryption) organization. Under a directive (revised version of the National Security Council Intelligence Directive (NSCID) No. 9) from President Truman and the National Security Council, the NSA was formed in November of 1952. The organization exists to protect national communications systems integrity, and to seek information about foreign adversaries'...