Japanese scientists have stored 5Mb of data on a human fingernail using laser etching of three-dimensional optical memory.

Data was recorded in three layers using extremely short laser pulses lasting a trillionth of a trillionth of a second. These caused micro-explosions in the nail's structure with the resulting depressions being read back using fluorescence readout, an optical microscope and charge-coupled device.

Details of the exploit were published in Optics Express. The news clipping can be read here.

According to the scientists involved, the potential of this technique is primarily seen in the biometric data field with human fingernails carrying encoded data that is not subject to theft, loss or forgery. The data lasts for about six months, the time a nail takes to grow from root to tip. After that it needs re-writing.

The recording density is 2GB per cubic centimetre. The scientists involved are now working on actual fingernail readers, having several issues to nail down.

There is no word on possible read-write techniques. It has been suggested that human couriers could transport 12.5MB of data quite securely using all their fingers and toes. The flash memory industry may be considering the implications of this new and very cheap recording medium. Scientists have not yet investigated the effects of fingernail laquer and varnish which might corrupt fingernail data reading devices in the future.