Disadvantage of Using Java Ring

Although, Java Ring can be the most secure storage medium for many industries, the cost of implementing the system could be very high. Even though ibutton can be purchased for cheaper price, in order to function, it needs a receiver such as blue dot receptor which could be very
expensive. Also, it needs a high level tools and method in order to program application efficiently, reliably, securely.

A Java Ring-based system doesn’t automatically allow user mobility. The problem with the Java Ring that many of the organization don't even know the existence of Java Ring. User mobility is only possible if every machine that the user accesses has a iButon reader attached. The machine must support the same standard ibutton reader interfaces or use the same proprietary iButton reader.

iButton has a limited processor power and memory. For better performance and scalability it is imperative to move the processing load to the application server. Also only limited amount of information can be stored which means an individual might need to carry more than one Java Ring. Carrying the Java Ring everywhere could lead to theft issues .

References:
http://people.cs.uchicago.edu/~dinoj/smartcard/javaring.html
http://www.javaworld.com/javaworld/jw-04-1998/jw-04-javadev.html?page=2
http://www.javaworld.com/javaworld/jw-04-1998/jw-04-javadev.html?page=3