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(ii) Iris and Retinal Recognition: Biometrics that analyse the complex and unique characteristics
of the eyes can be divided into two different types:
Iris biometrics: The iris is the coloured ring of tissue that surrounds the pupil of the eye.
An iris recognition system uses a video camera to capture the sample, while the software
compares the resulting data against stored templates.
Retina biometrics: Retina is the layer of blood vessels at the back of the eye. A retinal
recognition system projects an infrared light beam into eye, which is placed closed to the
signal receiver. The unique patterns of the retina are then extracted and analysed by the
system to grant access.
Tech Fact
For iris and retinal recognition, it is advisable to remove eye glasses and contact lenses.
(iii) Voice Recognition: The term voice recognition refers to identifying the person who is speaking,
rather than what he/she is saying. Recognising the speaker can simplify the task of translating
speech into system trained on a specific person’s voice, or it can be used to authenticate or
verify the identity of a speaker as part of a security process.
Encryption: Encryption is the process of converting data and information into a form, called
ciphertext, that cannot be easily understood by unauthorised people.
Decryption: Decryption is the process converting encrypted data back into its original form,
so that it can be understood.
The use of encryption and decryption is as old as the art of communication. In earlier times,
particularly during wars, a cipher, often referred to as a code, was used to prevent enemies from
accessing the contents of transmissions.
Simple ciphers include the substitution of letters for numbers, the rotation of letters in the
alphabet, and the ‘scrambling’ of voice signals by inverting the sideband frequencies. Some
complex ciphers work according to sophisticated computer algorithms that rearrange the data
bits in digital signals. For example, take a look at the following code:
Jogpsnbujpo Qspufdujpo
Do you understand the code or does it make any sense? No. This is because it is written in
encrypted form. However, if you know the decryption method you can decipher it.
Try replacing every letter in the message with the letter precedes it in the alphabet. You will find
that the code is:
Information Protection
HOW TO BACKUP YOUR IMPORTANT FILES?
In this section, you will learn how to back up your computer files. This is an important step in ensuring
the safety of your data. Have you ever lost any important documents, photos or other files? Imagine
what would happen if your computer suddenly stopped working.
Computer Safety and Security 69

