Introduction
Magstripe has been widely used in various kinds of applications such
as financial, access control or closed stored-value cards with the benefit
of high reliability, low cost and a worldwide installed infrastructure.
The rewritability is a very important feature of magnetic recording
media. On the other hand, the rewritability of magstripes makes alteration
possible, and it can be considered a fatal property. The rewrite capability
is essential in some types of magstripe cards, however it is responsible
for inconsistent reads due to magnetic damage and allows tampering of
the encoded data. The magnetic damage can be eliminated by increasing
the coercivity of the magstripe. However, as long as the rewrite capability
exists, we are essentially unable to ensure the magstripe is tamper
proof.
Hitachi Maxell, Ltd. has developed a new magnetic pigment "Maxeron"
which creates a fundamentally different branch of magstripe techno-logy.
A virgin magstripe produced with this pigment has an effective coerci-vity
which enables it to be encoded by an ordinary high coercivity (HiCo)
encoder. This original encoding process produces a remarkable increase
of coercivity, which is beyond the rewrite capability of a standard
magnetic recording head. These revolutionary properties protect the
magstripe from card fraudulence by prohibiting re-enco-ding of data
and are essentially immune to any magnetic damage.
Technology of magnetic pigment
The new magnetic pigment is an inter-metallic compound compromised
of particles composed of manganese and bismuth unrelated to the gamma-ferric
iron oxide used in low coercivity (LoCo) or barium ferrite used in high
coercivity (HiCo) magstripes.
These new particles use different reversal modes to reverse their magnetic
polarity in the virgin production state and in the once-encoded state.
The "Maxeron" particles in their virgin state are easily magnetized,
but once-saturated these particles show extremely high coercivity.
Magnetic properties
The magnetization curve of the Maxell Stripe using the new particles
is shown in Figure 1 compared with that of a HiCo magnetic stripe (Coercivity:
2,750 Oersteads). The virgin "Maxeron" Stripe is saturated
under the lower magnetic field than that of the HiCo stripe. Figure
2 shows the saturation curve of Maxell and HiCo stripes. In Figure 2,
the effective coercivity of the Maxell Stripe is estimated to be around
1,800 Oersteads. The result means that the "Maxeron" Stripe
can be encoded by an ordinary high coercivity encoder.
On the other hand, once saturated, the Maxell Stripe shows extremely
high coercivity of around 15,000 Oersteads, as shown in Figure 1. Thus
the original encoding process produces a remarkable increase of coercivity
in the particles.
The stripe becomes extremely difficult to rewrite, because the required
field strength for rewriting is beyond the capability of a standard
magnetic recording head.
Figure 3 shows the erasing curves of the "Maxeron" and HiCo
stripes. The signal amplitude of the HiCo stripe becomes nearly zero
by applying the erasing current of 100 mA. On the other hand, the Maxell
Stripe keeps the signal amplitude above 90% even under the erasing current
of 500 mA.
Benefits
This once-encoded coercivity is so high that the encoded data can not
be rewritten for the data densities involved in magnetic technology.
Moreover, this ultra-high coercivity of a once-encoded stripe means
that the data is immune to any magnetic damage.
The Maxell Stripe creates a new and different branch of magnetic technology,
but is not intended to, and does not, replace the existing magnetic
stripe technology. The two technologies will coexist side-by-side, depending
on the application or requirement. If we need the rewrite capability,
we will use the conventional LoCo or HiCo stripes. If we need read-only
capability, we will use the "Maxeron" Stripe. If we need both
on the same card, we will use two stripes, one conventional stripe and
one Maxell stripe.
This operational compatibility with ordinary magstripes means that
the "Maxeron" Stripe can be used to increase the security
and extend the life of an existing system, ultimately arriving at maximum
security on a cost-effective basis.
Applications
The ultra-high coercivity of the encoded Maxell Stripe offers another
advantage to magnetic stripe applications. A magnetic erase field strong
enough to erase any known high coercivity stripes will not damage the
"Maxeron" Stripe. This feature can be used to eliminate HiCo
counterfeits or copies (skimming).
The erase test can be performed before reading the card in a standard
reader, by swiping the card through an inexpensive rare-earth eraser.
The erasure test can be performed simultaneously with reading the card
in a reader equipped with an eraser. Either way, only a genuine Maxell
stripe can survive the erasure test, and yield valid read data.
Summary
The "Maxeron" Stripe is made of new magnetic particles developed
by Hitachi Maxell, Ltd. Unrelated to conventional particles used in
LoCo or HiCo stripes, the stripe can be only encoded once, and this
can be done with a standard HiCo encoder. The original encoding increases
the coercivity to an ultra-high value whereas any encode head can not
rewrite the data, although it can be read by any standard magstripe
reader.
Thus the Maxell Stripe is fully compatible with standard magnetic stripe
equipment with the exception that it can only be encoded once. The encoded
data can neither be altered nor magnetically damaged.
For maximum security, the erasure test can be performed before reading,
which will not damage the Maxell stripe, but will eliminate HiCo counterfeits
or copies (skimming).