vault backup: 2022-08-01 10:00:53

content/notes/03-more-css.md

@@ -4,9 +4,9 @@ aliases:
 tags: 
 - cosc203
 - lecture
-sr-due: 2022-07-31
+sr-due: 2022-08-25
-sr-interval: 7
+sr-interval: 24
-sr-ease: 250
+sr-ease: 270
 ---
 
 [slides](https://blackboard.otago.ac.nz/bbcswebdav/pid-2964467-dt-content-rid-18940944_1/courses/COSC203_S2DNI_2022/COSC203_lecture3%281%29.pdf)

content/notes/06-6809-programming.md

@@ -40,7 +40,7 @@ calling routine
 bsr routine
 ```
 
-## Interation
+## Iteration
 use GOTOs
 
 ```

content/notes/6809.md

@@ -0,0 +1,18 @@
+---
+title: "6809"
+aliases: 
+tags: 
+- cosc204
+---
+
+
+# Routines
+
+# Iteration
+
+# Input/Output
+
+# Hello World
+
+# Assembler
+

content/notes/comp-210.md

@@ -18,11 +18,14 @@ No final exam
 - [mccumber-cube](notes/mccumber-cube.md)
 - [access-security-tradeoff](notes/access-security-tradeoff.md)
 - [cia-triad](notes/cia-triad.md)
+- [cryptography](notes/cryptography.md)
+- [randomness](notes/randomness.md)
 
 # Lectures
 - [01-big-picture](notes/01-big-picture.md)
 - [02-concepts-and-roles](notes/02-concepts-and-roles.md)
 - [03-threats-social-engineering-and-failures](notes/03-threats-social-engineering-and-failures.md)
+- [04-authentication-authorisation-passwords](notes/04-authentication-authorisation-passwords.md)
 - [05-cryptography](notes/05-cryptography.md)
 
 # Archive

content/notes/cryptography.md

@@ -13,5 +13,31 @@ Edward snowden said
 
 >"arguing that you don't care about privacy because you have nothing to hide is no different than saying you dont care about free speech because you have nothing to say."
 
+# History
+One of the earliest known ciphers was the simple subsitution cipher used by julius caesar named the caesar cipher. 
 
+Although it a very bad cipher, it still uses the same general process of encryption and decryption. 
 
+# General Process
+- encrypt
+	- plaintext + key => ciphertext
+	- key is a secret
+- decrypt
+	- ciphertext + key => plaintext
+
+mathmatically
+- c = e(p, k)
+- p = d(c, k)
+
+# Randomness
+[randomness](notes/randomness.md) is the basis for the theory of cryptography. The aim of encryption is to alter a message (or binary sequence) so that it is maximally random i.e., has the highest entropy, and to remove any sort of pattern. 
+
+# Terminology/Conventions
+- alice, bob, charlie, etc
+- mallory -> malicious
+- etc
+- public vs private domains
+	- assume communication is public
+	- assume information is prepared and consumed in private domain
+- copy from lecture 5 slides
+- 

content/notes/randomness.md

@@ -5,4 +5,36 @@ tags:
 - comp210
 ---
 
+- a lack of predicability
+- no patterns
+- stochastic (can be analysed but not predcted) vs deterministic
 
+used for
+- one time pad
+- generating key-pairs
+- generating salts for password hashing
+- seeding pesudo random number generators
+
+humans are not good at randomness
+- e.g., see patterns when there are none
+- e.g., random dot pattern
+- shuffle algorithm
+- gambers fallacy
+
+how to prove randomness
+- cannot prove
+- but can check for uniformity, bias, distribution etc. 
+- difficult with small samples
+- can identify data that is unlikely to be random
+	- (rngtext, diehard, dieharder etc)
+
+# In computers
+computers have the same problem: they are deterministic
+- cannot really produce true random numbers
+- CSPRNGS crypto secure pseudo random number generators
+- hardware entropy generator
+
+entropy pool
+- modern OSs implement an entropy pool that processes can draw on when the need random data
+	- some systems provide blocking and non-blocking random source devices
+		- blocking: will stop when entropy is exhausted