Knuckletop Computing: The Java Ring
Aside from the different Smart Cards, a number of various devices powered
by the Java Card has been introduced. Some of them have a form factor that
is aimed to support a more rugged environment than traditional plastic
One of the first impressive devices powered by the Java Card technology
came in the form of now famous Java Rings at the Sun's JavaOne
conference, in March 1998. The rings were issued to the conference attendees
when they picked up their materials at registration. With one of these
rings a user could communicate with the computers at the Hackers' Lab,
help build a large fractal image at the show, or even get a cup of
their favorite coffee.
Inside the Java Ring - Java iButton
The Java Ring is an extremely secure Java-powered electronic token with
a continuously running, unalterable real-time clock and
rugged packaging, suitable for many applications. The jewel of the Java
Ring is the Java iButton -- a 16 mm one-million transistor, single-chip
trusted microcomputer with a Java virtual machine (JVM) housed in a rugged
and secure stainless-steel case. Designed to be fully compatible with the
Java Card 2.0 standard the processor features a high-speed 1024-bit
modular exponentiator for RSA encryption, large RAM and ROM memory capacity,
and an unalterable real-time clock. The packaged module has only a single
electrical contact and a ground return, conforming to the specifications
of the Dallas Semiconductor 1-Wire bus. Lithium-backed non-volatile SRAM
offers high read/write speed and unparalleled tamper resistance through
near-instantaneous clearing of all memory when tempering is detected, a
feature known as rapid zeroization.
Data integrity and clock function are maintained for more than 10 years.
The 16-millimeter diameter stainless steel enclosure accommodates the larger
chip sizes needed for up to 128 kilobytes of high-speed nonvolatile static
RAM. The small and rugged packaging of the module allows it to attach to
various accessories (key fob, wallet, watch, necklace, bracelet,
With a 32-kilobyte Java Card Environment (JCE) and I/O subsystem in
mask-programmed ROM, a continuously running true-time clock, and 6 kilobytes
of NVRAM memory with expansion potential up to 128 kilobytes, the Java
iButton supports a true Java stack, full-length 32-bit Java integers, and
garbage collection. This feature mix provides support for relatively high-end
Java applets with substantial computing requirements. While the Java iButton
can support the commerce models that have traditionally been the province
of credit cards, its greatest promise appears to lie in its capacity to
interact with Internet applications to support strong remote authentication
and remotely authorized financial transactions. The use of Java promotes
compatibility with these applications by providing a common language for
all application programming.
Layout of the iButton Structure
transferred between iButton and a PC with a momentary contact, at
up to 142K bits per second. To do that one presses iButton to the Blue
Dot receptor, a $15 pipeline into PC. The Blue Dot sticks to any convenient
spot on the front of a PC and is cabled to the serial or parallel port
in the back.
the Dallas Superconductor's information, over 41 million iButtons
are currently in circulation. List of the major users include the U.S.
Post Office, entire truck fleet fitted with iButtons that track vehicle
maintenance; Citizens of Istanbul, Turkey, who store digital cash
in the iButton, using the device as a small change purse on their mass
transit system. it was also said that the U.S. Postal service has approved
the cryptographic iButton as a Postal Security Device to be used in its
PC Postage program that allows individuals to download postage off the
Internet and print it from their own printers.