T

T1, T3:

A digital circuit using TDM (Time-Division Multiplexing).

Tamper:

To deliberately alter a system's logic, data, or control information to cause the system to perform unauthorized functions or services.

TCP/IP:

A synonym for 'Internet Protocol Suite', in which the Transmission Control Protocol and the Internet Protocol are important parts . TCP/IP is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network (either an intranet or an extranet).

Technical safeguards:

The technology and the policy and procedures for its use that protect electronic protected health information and control access to it. [45 C.F.R. § 164.304]

TELNET:

A TCP-based, application-layer , Internet Standard protocol for remote login from one host to another.

Threat:

A potential for violation of security, which exists when there is a circumstance, capability, action, or event that could breach security and cause harm.

Threat vector:

The method a threat uses to get to the target.

Token ring:

A token ring network is a local area network in which all computers are connected in a ring or star topology and a binary digit or token-passing scheme is used in order to prevent the collision of data between two computers that want to send messages at the same time.

Topology:

The geometric arrangement of a computer system. Common topologies include a bus, star, and ring. The specific physical, i.e., real, or logical, i.e., virtual, arrangement of the elements of a network.

Transaction and Code Sets:

See code sets

Transmission Control Protocol (TCP):

A set of rules (protocol) used along with the Internet Protocol to send data in the form of message units between computers over the Internet. While IP takes care of handling the actual delivery of the data, TCP takes care of keeping track of the individual units of data (called packets) that a message is divided into for efficient routing through the Internet. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent.

Transport Layer Security (TLS):

A protocol that ensures privacy between communicating applications and their users on the Internet. When a server and client communicate, TLS ensures that no third party may eavesdrop or tamper with any message. TLS is the successor to the Secure Sockets Layer.

Triple DES:

A block cipher, based on DES, that transforms each 64-bit plaintext block by applying the Data Encryption Algorithm three successive times, using either two or three different keys, for an effective key length of 112 or 168 bits.

Trojan Horse:

A computer program that appears to have a useful function, but also has a hidden and potentially malicious function that evades security mechanisms, sometimes by exploiting legitimate authorizations of a system entity that invokes the program.

Tunnel:

A communication channel created in a computer network by encapsulating a communication protocol's data packets in (on top of) a second protocol that normally would be carried above, or at the same layer as, the first one. Most often, a tunnel is a logical point-to-point link-i.e., an OSI layer 2 connection-created by encapsulating the layer 2 protocol in a transport protocol (such as TCP), in a network or inter-network layer protocol (such as IP), or in another link layer protocol. Tunneling can move data between computers that use a protocol not supported by the network connecting them.