Make like a spy: the art of invisible ink.
A nice little touch on how to include messages in
a letter that are hard for outsiders to spot.
Arrange, preferably face-to-face and not by
phone, a code that may be included either with
the address or in the letter itself.
Let us say, for instance, that you would usually
start off a letter to a friend with the phrase
"Dear Nick". Now, say that you wish to include
something - a phone number, for instance - that
you do not wish someone intercepting or later
finding the letter to stumble on. You may then
arrange with Nick, that in this case you will
instead start off with spelling out his name in
full, i.e. "Dear Nicholas".
If Nick receives such a letter, he will know that
sensitive info is included somewhere. How to
avoid detection of such info by a third party
with prying eyes?
By writing it in the equivalent of "invisible
ink". Visit a large stationery store or a
graphics tools supply house and get a UV-marker.
Anything you write with the UV marker (a phone
number, address or other secret message) will be
invisible to the naked eye. For "Nicholas" to
read your sensitive info, he will have to use a
hand-held UV (ultra violet) lamp of the sort
commonly used by stamp collectors. UV-lamps are
freely and cheaply available in photo stores or
stamp emporiums, for instance. Price, about $10
for the marker and less than $20 for the UV-lamp.
As an aside, UV-lamps are what leads to the
capture of most people travelling on false
passports. When examining a passport, the customs
or immigrations official will put the passport
under a UV-lamp to check whether the original
photo in the passport has been removed or altered
after being treated with fluid solvents. If it
has, the passport is immediately established as
being fake without having to resort to checking
with the issuing embassy or even Interpol
listings of stolen, blank passports. Most
countries mark passports with UV codes. Fake or
altered passports show up under UV light.
You can obtain cheap UV pens by mail order if you
ask for "Edding" UV Security markers and the
Austrian company Trodat who also supply UV stamp
pads and UV ink for fountain pens.
One minor problem with UV pens and ink is that
the products have only a short shelf life so you
need buy fresh to ensure efficiency. Ultraviolet
pencils in various base colors gave indefinite
shelf life. UV ink as used on passports usually
is sealed airtight and has longer life than
ordinary ink.
A useful item available rom some security
companies is a "envelope privacy protector",
consisting of standard letter-sized sheets of
paper completely coated with magnetic ink on one
side and colored ink on the other. Short of
physically opening the envelope, these sheets
should protect post communications from almost
any attack, including electronic scanning and
envelope compromise spray.
