1)When a person uses a money machine to get cash, is this message
authentication, an entity authentication, or both?
2) In a university, a student needs to encrypt her password (with a unique
symmetric key) before sending it when she logs in. Does encryption protect
the university or the student? Explain your answer.

What is the definition of engineering

Design a TDM system to handle 3 PAM channels if the maximum input frequency of each channel is 5 kHz.

1)Add the following in binary.a.1011 + 1010b.1111 + 0011
2)Add the following numbers using 2’s complement to represent the numbers. Use a bit length of 8 bits.a.20 + 10b.-10 + 20
3)What is the largest negative 8 bit, 2’s complement number? What is the largest positive 8 bit, 2’s complement number?
4)A – B = A + (-B). Therefore subtraction can be done with addition if the sign of B is changed. Using 8 bit, 2’s complement addition, perform the following operations.a.24 + (-14)b.-24 + (-14)
5)What is the decimal value of 11111111111111111111111111111101 if the number is in 2’s complement.
6)Use a 2-to-4 decoder and one OR gate (for the sum) to create a half adder.
7)Use a 3-to-8 decoder and two OR gates (one for sum and one for carry) to create a full add

Design and draw a zener voltage regulator to provide 12V output if load resistance
varies between 100 and 200. Assume that the input unregulated dc voltage is
18V and minimum zener operating current is 10 mA. Calculate the wattage of the
Zener diode, value and wattage of RS.

Design an adder circuit using op-amp to satisfy following equation:
Vo = V1 + 3 V2 + 2 V3 + 2V4 + 4V5
The supply voltage of the op-amp is 13V and output saturation voltage is 12 V.
The circuit should always operate in its linear range. What are the minimum-
maximum voltage values of V1, V2, V3, V4 and V5 when only one of them is
connected to the input at a given time (i.e. other input voltages are zero)? What is the
value of maximum voltage Vi if V1 = V2 = V3 = V4 = V5 = Vi ?)

Design and draw voltage regulator to provide 4 to 10V variable output voltage using IC 7812.

Design an adder circuit using op-amp to satisfy following equation:
-Vo = V1 + 3 V2 + 2 V3 + 2V4 + 4V5
The supply voltage of the op-amp is +/- 13V and output saturation voltage is +/- 12 V.
The circuit should always operate in its linear range. What are the minimum-
maximum voltage values of V1, V2, V3, V4 and V5 when only one of them is
connected to the input at a given time (i.e. other input voltages are zero)? What is the
value of maximum voltage Vi if V1 = V2 = V3 = V4 = V5 = Vi ?)

Design and draw a zener voltage regulator to provide 12V output if load resistance
varies between 100 ohm and 200 ohm. Assume that the input unregulated dc voltage is
18V and minimum zener operating current is 10 mA. Calculate the wattage of the
Zener diode, value and wattage of Rs.