The US Federal Reserve has issued a new
hi-tech $100 banknote comprising several
new security features.

It includes a blue 3D security ribbon and a bell
and inkwell logo that authorities say are
particularly difficult to replicate.
These combine with traditional security features,
such as a portrait watermark and an embedded
security thread that glows pink under ultraviolet
light.

The 2010 design was delayed because of
"unexpected production challenges".
The 3D security ribbon - which is woven into the
note, not printed on it - features images of 100s
that change into bells and move upwards or
sideways depending on how you tilt the paper.

Referring to the embedded security thread
Chadwick Wasilenkoff, chief executive of security
paper company Fortress Paper, told the BBC:
"It's not a small incremental step up for security,
it's a giant leap."

Tilting also reveals a green bell within a copper-
coloured inkwell to the right of the blue ribbon.
In addition, the 100 number in the bottom right-
hand corner shifts from copper to green.
The redesigned banknote, which features a
portrait of US founding father and scientist
Benjamin Franklin, also includes raised
"intaglio" printing that gives the notes a
distinctive feel, and microprinted words that are
difficult to read without magnification.
Forgeries

Over a decade of research and development has
gone into the new note, the Fed said, in a joint
project with the US Secret Service and the
Department of the Treasury.
Advances in design software and high-resolution
copying and printing have made it easier for
counterfeiters to print fake money and harder
for retailers to spot the forgeries.

US authorities say that $100 bill is the most
counterfeited of all US banknotes, but accurate
figures for the total value of counterfeit cash in
circulation are hard to come by.

The US Secret Service estimates that counterfeit
bills account for less than 0.01% of the $1.1
trillion (£683bn) of US money in circulation.
It says about $80.7m of counterfeit currency
changed hands domestically in 2012, and about
$14.5m abroad.

The authorities seized $9.7m in counterfeit cash
before it could make it in to the US money
supply, and seized $56.8m abroad in 2012.
Bruce Schneier, security expert at BT, told the
BBC: "Bills have to be easy to produce cheaply
and in large quantities by the government, yet
hard to reproduce in small quantities by
counterfeiters.
"Making something that costs less than a dollar
to produce and over $100 to reproduce is a very
difficult problem."