Consider a public-key Rivest-Shamir-Adleman (RSA) system with public key [899, 11] and private key [899, 611]. i) Encrypt the value 3. (3 points) ii) If knowing the encrypted value is 212, provide detailed decryption procedure. * Hint: Use square-and-multiply algorithm to calculate modular exponentiation (6 points) Through channel measurement, one can obtain the channel or overall impulse response at the receiver. For a received pulse pr(t), let pr(0) = 1,p(T) = -0.4, pr(2T) = 0.2, pr(-T) = -0.2, Pr(-2T) = 0.1. Design a 3-tap zero-forcing (ZF) equalizer. * Hint: Refer to Appendix A for the standard procedure of matrix inverse calculation. Given a packet switching network, the link bandwidth R and packet length L are 100 Mbps and 1500 bytes respectively. Answer the following questions: i) If two users have a communication distance (d) of 1000 kilometers, calculate the packet delay. "Hint: Assume the nodal processing and queueing delays are ignored. The signal propagation speed (s) is approximated to 2x109 m/sec. (3 points) ii) Suppose 50 users share the 100 Mbps link. Each user has a data rate of 20 Mbps when "active", and each user is active 5% of the time. What is the probability that more than 10% of users are active simultaneously? (4 points)