Small but perfectly informed

Will a Java Ring become the next must-have fashion accessory? Paul Lavin reports

In days of old, when knights were bold and nearly every one was illiterate, the impression of a signet ring in wax was one of the two ways that the authority and security of a document was ensured. The other way was, of course, at sword point.

Both swords and signet rings have fallen out of fashion as means of identifying people and transmitting their wishes securely, but the latter may be about to make a comeback - equipped with semiconductor chips and clever software that will provide proof of identity and content security, and perhaps a whole lot more.

At the recent JavaOne Conference in San Francisco, Sun Microsystems introduced the Java Ring, a mobile security device and data carrier cleverly disguised as a personal fashion accessory. The working part of the ring was a Dallas Semiconductor Crypto iButton in place of the jewel or engraved surface of a traditional signet ring.

The Crypto iButton has nearly a million transistors, and it implements a Java Virtual Machine, a bit of software that can handle communications and calculations and store data. Inside the 16mm steel case is a chip with a high-speed, 8-bit microprocessor, 32Kb of ROM, 6Kb of nonvolatile SRAM, a clock and a high-speed math accelerator for 1024-bit public key cryptography. Etched by laser into an unalterable ROM, its unique 64-bit registration number can be read by any application communicating with the iButton.

Java is the programming language that promises the ability to "write once, run anywhere", providing codesmiths with the widest possible audience for their software. At a stroke, Java can minimise the differences between a mainframe and a notebook PC - or a Java Ring - and enhance the ability of all of them to work together.

The Java Ring implements one of the best security techniques known. Security is enhanced if it is supplied by something you have and something you know - in the way bank cards and PINs combine to get money from a cashpoint. At the San Francisco conference, the rings were used for the mundane purpose of providing attendees with their preference in coffee. First the rings were personalised by pressing a special terminal called a Blue Dot receptor with the signet of the ring. The signet activated a computer where attendees filled out an online questionnaire that took personal information and coffee preferences and stored them back into the ring.

In JavaOne's Hacker Lounge, Sun had a fully automated coffee factory that took orders from an interface that read the customer's Java Ring. Clearly, the coffee demonstration was merely the thin end of the wedge; Sun was trying to drive home the point that Java programmers could write small applications - applets - that could be loaded into the ring and used to support a wide variety of security applications such as digital signatures.

The Java Ring is far more than a hacker's fashion statement. More than 21 million iButton devices are currently in use around the world. They can be found in medical information bracelets, in Schlage locks, in Ryder rental trucks, in every US postbox, in the cash safes of Taco Bell stores and in Federal Reserve banks in the US. Other applications are in the vending machines of Canada, the gas stations of Mexico City, the parking lots of Buenos Aires and the buses and ferries of Istanbul, according to Oliver Mills of Topsoft, UK agents for Dallas Semiconductor security devices. "They are inexpensive and rugged and offer almost uncrackable security for the data held within," Mills says.

Sun's downsized computing phenomenon, which it has christened "knuckletop computing", could open the door for many new personal cyber devices, including key chains, watches, pendants or anything wearable that could contain a chip. They are nearly indestructible - you can take thenm swimming or run them through the laundry - and they will remain unscathed, unlike smart chips on credit cards. The iButton has a 10-year lifespan and if anyone tries to pry it open to get at your digital signature or other secrets, the memory in the chip automatically zeros itself.

Importantly, you won't need more than one. The iButton supports multiple applets that can be loaded dynamically as you need them - to log into your PC, to get money from an ATM, to start your car or to exchange contact data with a business acquaintance. This Java Ring lets you roam both the real world and cyberspace with your personal preferences and personal data if not at your fingertips then at least close to your third knuckle.

Sun provided the scenario of starting your car with a Java Ring: the seats and mirrors would adjust automatically to the right position, your favourite radio station would tune in, and the car would compensate for your individual driving style, providing economy or performance as you prefer. With the combined ingenuity of Java developers, the number of uses for Java-enabled personal accessories seems limitless.

Dallas Semiconductor http://www.dalsemi.com/

Java Soft http://www.javasoft.com/

Topsoft (0171-633 9930: fax: 0171-633 9978)