Demonstrate that it is possible to make arbitrary changes to database values. Error-detection codes are built on the principle of longitudinal parity. Bits in the nth position of each byte have their s calculated and retained, whereas bits in the Oth place have their o calculated and kept, etc.

1. Basics: Each answer should consist of at most three sentences. (a) What does Kerckhoff’s principle say and why is it important? Give an example where Kerckhoff’s principle is violated. (b) Explain the advantages and disadvantages of a One-Time Pad. What is the connection between OTP and Stream Ciphers? (c) State if the following finite fields exist or not and why: GF(10) GF(16) GF(27) GF(66) GF(512)

Sketch a solution to automatically determine the best trace length for predicting replication policies in Globule.

Assume the following parameters for Selective Repeat (SR):  a) N = 4 b) Round Trip Time (RTT) = 10 ms c) Timeout period = 40 ms d) Segment Size = 2200 bytes. Suppose that Bob sent 14 segments, numbered 1 to 14, to Alice using the SR mechanism. Suppose that Segment 4 and Segment 10 were lost the first time the segments were sent to Alice (but reached Alice correctly when retransmitted). Apart from the above, there were no other segment losses. What is the average throughput obtained in sending all the segments (in bytes/sec)? Draw a diagram to show the communication of the segments in detail.