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Glossary of IT Terms

Information Security

Glossary A

This glossary contains industry standard and City specific IT terminology. The glossary should be consulted when policy, issue papers, etc. are drafted to ensure consistent use of terms across the City.

Hash (Hashing)
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Abend / Application Crash
Abend (derived from 'abnormal end') is where an applications program aborts, or terminated abruptly and unexpectedly. One of the prime reasons for a thorough testing of an organization's applications systems is to verify that the software works as expected. A significant risk to your data is that, if an application crashes it can also corrupt the data file which was open at the time.

A computer is simultaneously running multiple programs, each of which require the execution of a number of processes, often simultaneously. However, processes will usually interact with other processes and, due to the differences in hardware and load on the system, will execute at varying speeds. A process may abort when it fails to receive the expected input, or is unable to pass the output to a linked process. When a process aborts, it has the same effect as though that process had crashed. Poorly written applications may freeze /hang when one or more processes abort.

An individual whose primary aim in life is to penetrate the security defenses of large, sophisticated, computer systems. A truly skilled hacker can penetrate a system right to the core, and withdraw again, without leaving a trace of the activity. Fortunately such individuals are relatively rare, (although the numbers are growing), and the majority of those persons which the media are prone to call Hackers are really only Anoraks, Geeks, etc., or possibly Proto-Hackers who can penetrate some systems and leave childish messages to prove how smart they are. Proto-Hackers are those who aspire to Hackerdom but have not yet acquired the necessary skills to get past serious security measures without setting off alarm systems.

Hackers, of whatever variety, are a threat to all computer systems which allow access from outside the organization's premises, and the fact that most 'Hacking' is just an intellectual challenge should not allow it to be dismissed as a prank. Clumsy hacking can do extensive damage to systems even when such damage was not intentional.

Statistics suggest that the world's primary Hacker target - the Pentagon - is attacked, on average, once every three minutes. How many of those attacks are from Hackers and how many from Government Agencies, criminals, and terrorists, around the world is another question entirely.

The term is also applied (possibly unfairly) to those individuals who do not attack or attempt to penetrate computer systems, but use their skill to Hack commercially available packages, usually game software, to give themselves some advantage, make the game harder or different, etc. Such Hacks are often published in computer magazines as 'Hints, Tips, and Cheats' - much to the annoyance of the developers. This type of Hacker is not normally a threat to organization computer systems except, possibly those of game software development companies.

It states that a person must not carry out actions which amount to harassment, or which they know may be regarded by the other person as harassment. Claimants of harassment may be awarded damages for any anxiety caused by the harassment. An additional offence relates to putting the fear of violence on a person. In terms of Information Security, harassment by e-mail or via chat rooms may be punishable under this law.

Physical equipment:- processors, screens, keyboards, mice, printers, scanners, network routers, hubs, bridges, racking, disk drives, portable drives, etc.

Hash (Hashing)
Producing hash values for accessing data or for security. A hash value (or simply hash), also called a message digest, is a number generated from a string of text. The hash is substantially smaller than the text itself, and is generated by a formula in such a way that it is extremely unlikely that some other text will produce the same hash value.

Hashes play a role in security systems where they're used to ensure that transmitted messages have not been tampered with. The sender generates a hash of the message, encrypts it, and sends it with the message itself. The recipient then decrypts both the message and the hash, produces another hash from the received message, and compares the two hashes. If they're the same, there is a very high probability that the message was transmitted intact.

Hashing is also a common method of accessing data records. Consider, for example, a list of names:

  • John Smith
  • Sarah Jones
  • Roger Adams
To create an index, called a hash table, for these records, you would apply a formula to each name to produce a unique numeric value. So you might get something like:
  • 1345873 John smith
  • 3097905 Sarah Jones
  • 4060964 Roger Adams
Then to search for the record containing Sarah Jones, you just need to reapply the formula, which directly yields the index key to the record. This is much more efficient than searching through all the records till the matching record is found.

A large computer, running major applications and containing considerable quantities of data which is contacted through a network by subordinate computers (PCs, terminals, etc) for processing or information. Smaller hosts are generally known as servers.

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A hot site is a fully equipped, operationally ready data center offering specific hardware platforms ready for immediate use and provides all of the support equipement and resources an organization needs for immediate resumption of operations.