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(ii)   Iris and Retinal Recognition: Biometrics which analyse the complex and unique characteristics of
                      the eyes can be divided into two different types:
                          Iris biometrics: Iris is the coloured band 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 shoots an infrared light beam into eye that has been placed closed to the signal receiver.
                      Then, the genetic factors are entracted and analysed by the analyser 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 finding the identity of a person who is
                      speaking, rather than what he/she is saying. Recognising the speaker can simplify the task of
                      translating speech into system that has been 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 conversion of data and information into a form, called
                        ciphertext, that cannot be easily understood by unauthorised people.

                         Decryption is the process of converting encrypted data back into its original form, so that it can
                       be understood.
                         The use of encryption/decryption is as old as the art of communication. In older day, at the time
                       of war, a cipher, often called as code, was employed to keep the enemy away from obtaining 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
                       encripted form. However, if you know the decipher, you can decipher it.

                         Try replacing every letter in the message with the letter preceding it in the alphabet. You will find
                       that the code is:
                                                         Information Protection

                         HOW TO BACKUP YOUR IMPORTANT FILES?


                  Now you will learn how to back up your computer files. It is another important step for computer
                  safety. Have you lost any important documents, photos or other files? Imagine what would happen if
                  your computer suddenly stopped working.
                  It may be possible to repair your computer, but your files may be lost forever. Luckily, you can prevent


                  66    Premium Edition-VIII
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