A | B | C | D | E | F | G | H | I | J | K | L | M |
N | O | P | Q | R | S | T | U

Hack
Any software in which a significant portion of the code was originally another program. Many hacked programs simply have the copyright notice removed. Some hacks are done by programmers using code they have previously written that serves as a boilerplate for a set of operations needed in the program they are currently working on. In other cases it simply means a draft. Commonly misused to imply theft of software. See also: Hacker.

Hacker
Common nickname for an unauthorized person who breaks into or attempts to break into a MIS by circumventing software security safeguards. Also, commonly called a "cracker." See also: Intruder, Hack.

Hamiltonian path problem
A Hamiltonian path is a path through a graph that passes through each vertex exactly once. The associated problem is given a graph G is there a Hamiltonian path. This is a hard problem.

Handshake
A protocol two computers use to initiate a communication session.

Hash
Abbreviated term for cryptographic hash.

Hash Function
Term usually reserved for non-keyed message digests but sometimes is used to refer to both key and non-keyed digest functions.

Hashed Message Authentication Codes (HMACS)
A combination secret key and a non-keyed hash function designed to operate faster than a MAC but be just as secure. As of this writing most HMACs use SHA or MD5. Systems like Secure Socket Layers (SSL) and Internet Protocol Security (IPsec) have standardized on HMAC.

High Assurance Digital Certificates
A digital certificate issued to an applicant who most likely was required by the Certificate Authority (CA) to physically appear and present more than one additional form of identification, such as a driver’s license or a passport. It is high assurance since the CA can match a certified picture to the physical applicant.