For low level security applications, an organization intends to use a Vignere cipher to

encrypt telemetry data over a wireless link. An example of a packet data used is as

follows

79EF01 AFD902

(a) What is the advantage of the Vignere cipher over a simple substitution cipher?

(b) Design the cipher using modulo arithmetic to ensure that the system can be

implemented on a mobile computing device.?

(c) If the key is DF17, encrypt the example message FI 17.?

(d) Explain with the necessary calculations why it is desirable to use a key length of

8 characters compared to 4 characters.?

please answer all questions ?