Many of the readers of this article have
certainly had a chance to use a terminal with help of which transactions
are made in shops and restaurants by those customers using credit cards.
I do not of course refer to the equipment of the older type, called
"an iron," which transferred with a roller - as a stamp - the
convex letters onto a pre-printed form, but its modern successors. These
are small computers, which read the information encoded in a magnetic
strip or a chip contained in the card, posses a keyboard, display,
printer and also - this being quite important - can connect with bank
computers to check account standing, or to make money transfer. Those
devices are usually connected with electronic cashiers, and from the
point of view of the payer their handling is done by means of inserting
the card to a slot and entering so called PIN. Today it is assumed that
the number should be known only to the card's holder and to constitute
something, which univocally identifies and authorises a transaction.
This replaces in some way a signature placed previously on the
pre-printed forms being handled only with the "iron."
Unfortunately, and this is
probably nothing new to the readers of this article, such protections do
not constitute a significant barrier to offenders, dishonest card's
holders or employees of firms issuing such cards. The number of frauds
harming cards' holders and the cards' issuing firms constantly increases
and it seems that this tendency can be stopped only by a technology,
which will allow a 100% guaranteed recognition of the card's holder.
Such technologies have been being developed for some time now by various
firms and exist under a name of biometrics. Their creators hope that
with an assistance of analysis of voice, appearance, pattern of an iris
and, primarily, fingerprint lines, they will be able to provide
error-proof identification of people. Much points at that that the most
practical technology will be the one, which will enable error-proof
identification of fingerprints. It has been known for more than a
hundred years now that those patterns with no doubts whatever can
identify their owners. Unfortunately construction of such a piece of
equipment which will have the facility to perform this with equal
accuracy to dactylography specialists is not a simple task.
It so happens that
patterns of fingerprint lines possess low contrast and the classic
methods of their recognition are too sensitive to dirt, water, grease,
which by their nature are present on their surface, and also it is not
easy to ascertain that the examined object is really a finger - and more
so an alive one. In this article I will not attempt to consider the
problems connected with that and to discuss the existing ones or the
proposed solutions along with their benefits and drawbacks - this would
require a longer work. However I am going to present a solution, which
has a chance not only to ensure error-free identification of the card's
holder, but also to replace the today's terminal altogether.
Such a solution is being
developed in Optel, a firm based in Wrocław, which is based on the idea
that ultrasonic waves are the best medium for fingerprints recognition,
the method having been proposed in 1986 by the author of this article.
Construction of the piece of equipment that was based on this proposal
was not easy - it required mastering of many new solutions and many
years of work. The fruits of this work are prototypes protected with
many patents, and - quite constructionally advanced - a vision on what
the future version of the terminal may look like (and at the same time
the envisaged production scale version of this device). In my opinion
this may be of interest to readers of this article. Also because of the
fact that such a piece of equipment can be useful not only there where a
transaction is to be performed with a credit card, but also it can
replace the classic door locks, passwords for computer access, etc. This
does not have to be a very complicated device. Its basis will constitute
a glass plate, on which edges there will be placed transmitters and
receivers of ultrasonic waves. Under the plate there will be located a
liquid crystal screen. Apart from that this will also require employment
of electronics, which can be located in only a few chips. The whole
thing can occupy e.g. a square of 10 cm side (such dimensions will have
the first prototype of the device), although there are also possible
devices of larger or smaller dimensions.
The whole device is based
on the principle that contact of any thing with the plate's surface will
effect a change of way of propagation of sonic waves inside of it, which
allows observation of that thing which comes into contact with it. It
would be difficult to explain in detail in what way the device "sees"
what is happening on its surface in such a short article. To provide
only a brief explanation, there have been utilised for this purpose
ideas known from holography, although in configuration that has not been
seen before, and the whole device is nothing else but a holographic
acoustical camera - undoubtedly one its kind.
Images being produced by the
camera simply copy those places, which come into contact with the
plate. Then the fingerprint lines of the pressed-on finger can be seen,
but also of course it can be established where it is located. This
allows not only its recognition, but also - somewhat by the way -
elimination of a keyboard (since the whole plate is an equivalent of
today's touch screens and can constitute a virtual keyboard). Of course
a pencil can also get into contact with the screen and it can be
observed what position it is in. Undoubtedly the pencil can be also used
for writing or drawing, and the device will be capable of following its
movement - similarly to today's drawing pads. This function can be also
utilised for transfer of a signature. For recognition of the user there
is also another thing important: because ultrasonic waves partly
penetrate the pressed-on object, it is possible to ascertain if the
matter is a real skin or a silicon dummy; it is also easy to verify, if
the finger is alive, because of visibility of the blood circulating
through it. It is also worthwhile to mention that traces left by other
fingers - classic fingerprints - remain entirely invisible. Ultrasonic
waves - opposite e.g. to light - simply do not respond to them.
To provide the full
picture it can be also said that the whole device does not have to be
specially expensive, and because it will not have any mobile parts, it
can be expected to be very durable.
I suspect that inquisitive
readers have already noticed that the device could be used also for one
more purpose: as it can be easily noticed the relief of fingerprint
lines is a certain, specifically coded information, given to us by
the nature and telling something about human genes. One can easily
imagine that any given information can be encoded in this way, similarly
to the way stamps are made. If this is done on the surface of a credit
card, then an ultrasonic terminal could perform to some extend a similar
function to the classic "iron" - it will see the relief on the
surface and will read the information encoded in this way.
