From be5800abee3a4993661ac2a9a172f256742c55a5 Mon Sep 17 00:00:00 2001 From: shockrah Date: Sun, 29 Sep 2019 13:46:42 -0700 Subject: [PATCH] lulw --- 312/.gitignore | 1 + 312/hw/.gitignore | 2 -- 312/hw/1.md | 72 ----------------------------------------------- 312/hw/2/2.md | 59 -------------------------------------- 4 files changed, 1 insertion(+), 133 deletions(-) create mode 100644 312/.gitignore delete mode 100644 312/hw/.gitignore delete mode 100644 312/hw/1.md delete mode 100644 312/hw/2/2.md diff --git a/312/.gitignore b/312/.gitignore new file mode 100644 index 0000000..6ba5ec3 --- /dev/null +++ b/312/.gitignore @@ -0,0 +1 @@ +hw/ diff --git a/312/hw/.gitignore b/312/hw/.gitignore deleted file mode 100644 index cfa3cea..0000000 --- a/312/hw/.gitignore +++ /dev/null @@ -1,2 +0,0 @@ -makefile -*pdf diff --git a/312/hw/1.md b/312/hw/1.md deleted file mode 100644 index 92ce220..0000000 --- a/312/hw/1.md +++ /dev/null @@ -1,72 +0,0 @@ ---- -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. - - -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 - - diff --git a/312/hw/2/2.md b/312/hw/2/2.md deleted file mode 100644 index abc340c..0000000 --- a/312/hw/2/2.md +++ /dev/null @@ -1,59 +0,0 @@ ---- -title: Homework 2 -author: Alejandro Santillana ---- - - -# Section 1 - Symmetric Key Cryptography - -1. The two approaches to attacking a given cipher are using _brute force_ or _cryptanalysis_. Brute force methods are a simpler method of attack because they naively try all possible inputs for a given output. Cryptanalysis is the process of using the particular characteristics of a cipher to de-cipher the original message. - -2. Chosen plain text attacks involve using a given plain text to determine a cipher text. The attacker themselves choose the plain text and have some kind of cipher text available to them. The algorithm on the other hand is not known to the attacker when performing cryptanalysis. In this way a black box approach to reversing the cipher is taken. - -3. Cryptography is the study and practice of creating hidden messages from plain messages. Cryptanalysis is the practice of analyzing hidden messages to determine a plain message. - -4. Unconditionally secure ciphers are ciphers which are considered secure regardless of how many resources or time are given to reversing the cipher, sometimes due to not having enough information to determine anything useful. Computationally secure ciphers exist on the premise that it is impractical to attempt to break the cipher given a limited amount of compute power. - -5. Key distribution is the first major hurdle to ensure that the one time pad is used effectively. Without properly secure channels to share the key the scheme of a one time pad can not be trusted. The other issue is that the key must be longer than the message itself in order to ensure that parts of it are never reused. - -# Section 2 - -1. Encode: _This is an easy problem_. \ -Decode: _rmij'u uamu xyj_. \ -Plaintext letter: a b c d e f g h i j k l m n o p q r s t u v w x y z \ -Ciphertext letter: m n b v c x z a s d f g h j k l p o i u y t r e w q \ -``` -Encode portion: uasi si mncmiw lokngch -Decode portion: wasn't that fun -``` - - - -2. Plain Text: _Must see you over Cadogan West. Coming at once._ \ -Key: _largest_ -``` -Part A: - -L A R G E -S T B C D -F H I K M -N O P Q U -V W X Y Z -Encoded: UZTB DLG ZPN NWLG TGTUERO VLDB DUHFPE RH WQSRZ - -Part B: -Encoded: UZTB DLG ZPN NWLG TGTUERO VLDB DUHFPE RH WQSRZ - -``` - -3. Message: "_Let's skip class and go to the beach_" \ -Depth = 4 \ -``` -L S C S G T E - E K L A O H A - T I A N T E C - S P S D O B H -Message: LSCSGTEEKLAOHATIANTECSPSDOBH -``` - -