Working with capsules of dye just a few billionths of a metre in diameter, researchers at University of Toronto and the advanced optical microscopy facility at Toronto’s Princess Margaret Hospital have created a new strategy for encrypting photographs, signatures and fingerprints on security documents.
‘This technology will give security or customs authorities the confidence that documents are not fake,’ says U of T chemistry professor Eugenia Kumacheva, who holds the Canada Research Chair in Advanced Polymer Materials. ‘It gives a very high level of data encryption and is relatively cheap to produce.’
A thin film of polymer material is produced from tiny three-layer capsules comprising three different dyes, Kumacheva explained. Each layer is sensitive to light at a particular wavelength, ultraviolet, visible or infrared.
Using high-intensity irradiation, Kumacheva used differing wavelengths to encrypt several different patterns onto a security document.
To the naked eye, the identification document (a passport or smart card) might reveal a photograph, but under other detection devices could reveal signatures or fingerprints.
The technology could offer a speedy alternative to waiting in long line-ups at security checkpoints or government offices, said Kumacheva, who has secured a patent on the technology.