Secure data transmission
Secure data transmission means that data/information is not being received or modified by an unauthorized person, over a network, from source to destination.For secure data transmission, we can convert an actual message (which is in readable form) into an unreadable message (called an encrypted message) with the help of the concept of encryption. This unreadable message is sent through the network to the destination. If a hacker tries to read this message, he/she receives an unreadable message that cannot be easily converted into the actual message. The unreadable message can be converted to the original message by the receiver at the destination. Caesar Cipher is one of the common encryption techniques. In this technique, each letter of the word is replaced by a letter some fixed number of positions (usually called as key) down the alphabet. For example, if the key is 3, each 'A' will be replaced by 'D' (Letter 'D' is 3 positions down Letter 'A' in the alphabet), each 'B' will be replaced by 'E' and similarly, each 'Z' will be replaced by 'C'. The receiver can identify the original message by using the reverse technique of encryption. This reverse technique is called decryption.
(i) Secure data transmission means
a) Data can be accessed by any unauthorized person during transmission.
b) Data can not be accessed by any unauthorized person during transmission.
c) Transmission of data
d) None of the above
(ii) Which of the following techniques can be used for security of data.
a) Authentication
b) Authorisation
c) Encryption
d) All of the Above
(iii) Caesar Cipher is
a) used for conversion of the actual message into an encrypted message
b) an encryption technique
c) both (a) and (b)
d) None of the above
(iv) Person 'X' has received an encrypted message and wants to convert this message into the actual message (message before encryption). The technique he should use is called
a) Conversion
b) Encryption
c) Decryption
d) None of the above
(v) A sender wants to send a message having the text as 'COMPUTER' to a receiver using 4 as the key. What will be the encrypted message?
a) GSQTZXIV
b) GSQTYXIV
c) GSXTYXIV
d) GSQSYXIV
(vi) An encryption algorithm is used to transform a readable message into:
a) Text message
b) Simple message
c) Converted message
d) Encrypted message
(vii) In Ceaser Cipher, for which of the following values of key, the encrypted message will be the same as original message.
a) 0
b) 26
c) both (a) and (b)
d) None of the above
