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9.14.3 Short description

Research and development addressing the verification of identify and security of information and communication has been observed in this section. The use of nanomaterials in identity verification has been done demonstrated through its use in nanocomposites and protection of information and communication through quantum cryptography.

 

Nanocomposites - Biometrics are viewed to be vital in identification of a person's identity. Biometrics encompasses recognition method for human fingerprinting, iris and retinal, facial and hand features. Polymer nanocomposite material based on multi-dyes has been reported in literature for application in security labelling. Polymer multiphase nanostructured materials have been reported in the literature as a medium for recording biometric information. Fluorescent dyes with non-overlapping absorption and emission spectra have been used to record information by photo-bleaching of the dyes. Design, synthesis and fabrication of two different approaches - full color and monochromatic spatial arrangement of three biometric features, photograph, fingerprint and signature was demonstrated. The dyes used were anthracene, 4-amino-7-nitrobenzo-2-oxa-1, 3-diazole (NBD) and Nile Blue. The size of the An labelled core was reported to be 450nm, dye labelled layer as 15 nm and spacer layer as 160nm. Destructive readout using a low power laser was used to examine the information recorded on to the nanostructured material. The advantage of this approach is the longevity as the destructive readout can be used on a daily basis for 4 years of image being accessed [360, 361].

 

Opal based nanocomposites - Iridescence of stacked silica spheres known as natural opals is caused by interference of light with lattice planes [362, 363]. An industrially scalable approach for producing opals from polymer has been mentioned in the literature. Quantum dot doped polymers opals have been created for security applications by compression moulding of flexible films. Experimental research has demonstrated nanoparticulate carbon black in elastomeric opals produces remarkable change in colour under compression loading [364].

 

Nanotechnology based platforms of P-Ink and Elast-Ink have been mentioned as commercially viable options for authentication technology. Active color tuning of opal has been utilised in these technology solutions. One solution reversibly shrinks or expands on removal or application of a voltage to a metallopolymer opal. Opal embedded in a matrix of polyferrocencylsilane gel is termed as P-Ink.  The other solution is based on studying the reversible dimensional changes of an elastomeric opal that change based on application or removal of a mechanical force. Composite opal formed by combing opal with synthetic rubber, which when dissolved leaves a network of voids in a rubbery matrix known as elastomeric inverse. Due to the highly porous structure, and the color shift observed with increasing pressure can be utilised as a highly fingerprinting sensor for use in forensics, biometric security and authentication [365].

 

Optical Fibres - Optical fluorescent fibers randomly arranged have been suggested as a solution for anti-counterfeiting by Tracer Detection Technology Corporation. The fibers provide a constantly moving a non-repeating target, making counterfeiting difficult. A unique algorithmically generated code printed with the fibers, add to the security feature. The code optically read has mentioned the possibility of generating a duplicate is 1 in 1015. The advantage this technique offers over other is due to the difficultly in producing the same fluorescent dichroic fibers, producing the same emission behaviour at the detector wavelength, fibers of same length and shape. Other alternatives to fluorescent markers have been suggested as nanocrystalline materials, carbon nanotubes, fullerenes, dendrimers, nano-intermediaries and nano-composites. Fluorescent nanoparticles such as quantum dots, fluorescent polymer particles, silica coated fluorescent polymer particles, dye loaded latex nanobeads, and iron oxide nanoparticles have been mentioned. The application has been reported for pharmaceutical, designer and branded clothing [366].  

 

Quantum cryptography - Quantum cryptography is based on the quantum mechanics principles of uncertainty and entanglement.  Two known approaches are considered for quantum cryptography. The first approach is that using polarisation of photons, where the polarised photons representing bits of information. The vertical polarisation represents a zero state and horizontal polarisation represents one state. The information which is encrypted as diagonal polarisations is used as an encryption method. The second approach used is that of entangled photons, where the entanglement property utilises to transfer cryptic information. In this method both the sender and receiver get one photon from the entangled pair. Due to pairing of entangled photons the measurements of polarisation of light provides the same output at both ends. The measurements are added to give a string of zero's and one's to get the key [367]. The research on quantum cryptography has been successfully demonstrated in transferring funds between the Vienna City Hall and the Bank of Austria. Entangled photons have also been sent over a distance of 100 km by researchers at Northwestern University [181].

 

 

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Visits: 573, Published on: May, 18th 2009, 05:12 PM, Last edit: May, 26th 2009, 05:09 PM Size: 5 KByte

Tags: Nanocomposites, opal, optical nanofibres, quantum cryptography

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