In
computer
A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...
software
Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications.
The history of software is closely tied to the development of digital comput ...
, a time bomb is part of a computer
program that has been written so that it will start or stop functioning after a predetermined date or time is reached. The term "time bomb" does not refer to a program that stops functioning a specific number of days after it is installed; instead, the term "
trialware
Shareware is a type of proprietary software that is initially shared by the owner for trial use at little or no cost. Often the software has limited functionality or incomplete documentation until the user sends payment to the software developer. ...
" applies. Time bombs are commonly used in
beta
Beta (, ; uppercase , lowercase , or cursive ; or ) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Ancient Greek, beta represented the voiced bilabial plosive . In Modern Greek, it represe ...
(pre-release) software when the manufacturer of the software does not want the beta version being used after the final release date. One example of time bomb software would be Microsoft's
Windows Vista Beta 2, which was programmed to expire on May 31, 2007. The time limits on time bomb software are not usually as heavily enforced as they are on
trial software, since time bomb software does not usually implement secure clock functions.
History
The first use of a time bomb in software may have been in 1979 with the
Scribe
A scribe is a person who serves as a professional copyist, especially one who made copies of manuscripts before the invention of Printing press, automatic printing.
The work of scribes can involve copying manuscripts and other texts as well as ...
markup language and word processing system, developed by
Brian Reid. Reid sold Scribe to a software company called Unilogic (later renamed Scribe Systems), and agreed to insert a set of time-dependent functions (called "time bombs") that would deactivate freely copied versions of the program after a 90-day expiration date. To avoid deactivation, users paid the software company, which then issued a code that defused the internal time bomb feature.
Richard Stallman
Richard Matthew Stallman ( ; born March 16, 1953), also known by his initials, rms, is an American free software movement activist and programmer. He campaigns for software to be distributed in such a manner that its users have the freedom to ...
saw this as a betrayal of the programmer ethos. Instead of honoring the notion of share-and-share alike, Reid had inserted a way for companies to compel programmers to pay for information access
(see
Events leading to GNU).
Comparison of logic bombs and time bombs
The main differences between
logic bombs and time bombs is that a logic bomb may have a timing function implemented into it as a failsafe if the conditions are not met in a certain time period (it may delete itself or activate its payload using the timing system), while time bombs only use timing functions to (de)activate themselves.
Time bombs, once activated, will unload their payload (which may be malicious) in a similar way logic bombs deliver their payloads to the target. The main difference between both time and logic bombs, and
fork bomb
In computing, a fork bomb (also called rabbit virus) is a denial-of-service (DoS) attack wherein a process continually replicates itself to deplete available system resources, slowing down or crashing the system due to resource starvation.
...
s, is that a fork bomb has no payload ''per se'', and instead does its damage by continually replicating itself to deplete available system resources.
See also
*
Logic Bomb
*
Planned obsolescence
In economics and industrial design, planned obsolescence (also called built-in obsolescence or premature obsolescence) is the concept of policies planning or designing a good (economics), product with an artificially limited Product lifetime, u ...
*
Scribe Time-bomb
*
Time bomb
A time bomb (or a timebomb, time-bomb) is a bomb whose detonation is triggered by a timer. The use or attempted use of time bombs has been for various purposes including insurance fraud, terrorism, assassination, sabotage and warfare. They are a ...
References
Software licensing
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