Fingernails store personal information

Secure optical data storage could soon literally be at your fingertips thanks to work being carried out in Japan. Yoshio Hayasaki of Tokushima University and colleagues have discovered that data can be written into a human fingernail by irradiating it with femtosecond laser pulses. Capacities are said to be up to 5 mega bits and the stored data lasts for 6 months -- the length of time it takes a fingernail to be completely replaced.

This should stop fingernail biting :-)