Fraud And Forgery
A schoolboy computer whizzkid penetrates the military computers controlling
the US missile system and convinces experts there that a World War
is about to start.
Fortunately, it all takes place in a movie - War
Games released in the USA in 1984 and in the UK in 1986. But such fantasies
about 'hacking' - as this activity is called - have come close to the truth.
In 1985, seven teenagers were found guilty of hacking their way into computer
systems controlled by the Pentagon, the US Military High Command headquarters,
in Washington.
By the time the FBI (Federal Bureau of Investigation)
caught up with them, the hackers had access to information that would allow
them to alter the position of American weather satellites.
Many computers protect their stored information
by insisting that a password is typed into the machine before access is
allowed. Commercial computer networks, such as British Telecom's Prestel,
have elaborate protection devices. But even these have fallen before the
determined hacker.
While hackers are becoming a serious menace to commercial
companies who keep all their records on computer, far more dangerous are
employees who use their knowledge of the company's passwords and accounting
methods to syphon off cash for themselves.
Computer fraud is merely the more glamorous form
of a criminal activity that has beeb around as long as clever and skilled
people have been able to simulate anything valuable, from passports to
paintings and perfumes.
Spotting the fake
The most basic weapon in detecting fraud in a document is a sharp eye.
Usually an experienced forensic scientist will first look for obvious clues,
and then seek the aid of instruments, starting with a lowpower microscope.
Most paper is manufactured with a particular watermark
- an almost invisible, transparent symbol which can be seen when the paper
is held up to the light. The mark is made when the paper is manufactured.
It can be imitated using a wooden stamp and olive oil. However, the false
imprint has sharper edges than the orginal, and can be detected using a
microscope.
Another way of checking a suspected fraud, such
as a faked signature, is by viewing it under ultraviolet light. If the
original signature has been removed, the impression it left will show up
under the light.
For futher investigation, the object, or a small
portion of it, is subjected to chemical analysis.
Gamma ray dating
To determine its true age, a sample of an object may be made radioactive.
The rate and intensity of gamma rays it emits can then be used to accurately
calculate the age.
The disadvantage of this method is that it leaves
the sample highly radioactive, and so it must be kept well shielded afterwards
to avoid dangerous radiation from it.
Ancient artefacts able to withstand great heat,
such as pottery, can be distinguished from fake lookalikes by method known
as thermoluminescene. When the clay is fired to about 600 Celcious, it
emits energy in the form of light, which can then be measured to calculate
the date of origin of the clay.
Printing money
Banknotes have always attracted the attention of counterfeiters, and
modern technology is making it much easier to produce high-quality
colour copies of printed material. However, the companies responsible
for designing and printing banknotes have introduced various measures to
make realistic copies difficult to produce and to make foegeries easy to
detct.
Modern banknotes bear intricate designs containing
numerous fine lines, originally made in metal by a master engraver. Such
fine detail is extremely difficult to copy, even using the reproduction
equipment. Other security measures include the use of intaglio (sunken)
printing to give the notes a characteristic 'feel', special threads incorporated
in the paper, the use of watermarks, and the individual number of the notes.
Some notes are printed with a fluorescent metallic int, the appearance
of which is impossible to reproduce by normal copying techniques.
Some of the most attractive forgeries have been
made by painters accomplished enough to imitate a great master. Their motives
are varied, from frustration to resentment againt the established art world.
If their art does not give them away, their materials do. Paints, pigments
and techniques have changed greatly over the years, and sophisticated chemical
detection means it is now extremely difficult to cheat the forensic scientist.
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