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(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
TAKING BACKUP OF 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 this by creating backup copies of all
of your files (or just the important ones) on an external hard disk drive or an online backup
service.
External Hard Disk Drives
To keep your file safe, you can purchase an external hard disk
drive and copy the content of your computer on it. The initial backup
could take several hours. Follow-up backup should be conducted on a
regular basis, but it may not take long because the drive will only need
to copy your most recent files. External Hard Disk Drive
Computer Safety and Security 67

