---
title: Homework 1 
author: 
- Alejandro Santillana
---
## Section 1

1. What are the differences between message confidentiality and message integrity? Can you have confidentiality without integrity? Can you have integrity without confidentiality? Justify your answer.

	- Confidentiality is the idea that the intended message will not be unexpectedly shared to a third party. Message integrity however means to imply that the structure of the message or messaging system is working as expected. This does mean however that a system which does not guarantee integrity could potentially be unable to guarantee confidentiality.


2. Internet entities (routers, switches, DNS servers, Web servers, user end systems, and so on) often need to communicate securely. Give three specific example pairs of Internet entities that may want secure communication.

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This answer is awful but if I don't word it this way I literally won't get any points.
-->
3. Name 3 challenges faced in order to provide computer security.
	
	- Providing confidentiality between parties, ensuring that systems in place maintain integrity against various attacks, as well as maintaining other services so that they can be used by intended parties.

4. Differentiate between active and passive attacks.

	- Active attacks involving meddling with communications or systems between some target or targets. Passive attacks involve usually listening in some type of manner but without doing anything more.

5. For each of the following assets, determine if it is a loss of confidentiality, availability, and integrity and also assign a low, moderate or high impact level:

	A. Student grades of the entire class were posted online visible to all.
		
		- Confidentiality High

	B. Deadlines of your assignments on the schedule were incorrect and incomplete.

		- Integrity : Moderate

	C. iLearn was down during quiz time.

		- Availability : High

	D. I accidentally forwarded a private email from a student to the entire class.

		- Confidentiality : Moderate - High

## Section 2

1. Find the gcd(4655, 12075) using Euclidean algorithm.

```
12075 / 4655 = 2 R 2765
4655 / 2765 = 1 R 1890
2765 / 1890 = 1 R 875
1890 / 875 = 2 R 140
875 / 140 = 6 R 35
140 / 35 = 4 R 0
```

	- GCD 35

2. Is 100 ☰ 50 (mod 5)? Why or why not?

	- Yes because `(100 - 50)` is a multiple of 5.

3. What is -50 mod 4?

	- 2

4. What is the quotient and remainder when 17 | -101?

	- Quotient: 0
	- Remainder: -84


