From 110ed00eb90d49b41b586c4310b1711da500e8f7 Mon Sep 17 00:00:00 2001 From: Jet Hughes Date: Mon, 1 Aug 2022 10:00:53 +1200 Subject: [PATCH] vault backup: 2022-08-01 10:00:53 --- content/notes/03-more-css.md | 6 +++--- content/notes/06-6809-programming.md | 2 +- content/notes/6809.md | 18 ++++++++++++++++ content/notes/comp-210.md | 3 +++ content/notes/cryptography.md | 26 ++++++++++++++++++++++ content/notes/randomness.md | 32 ++++++++++++++++++++++++++++ 6 files changed, 83 insertions(+), 4 deletions(-) create mode 100644 content/notes/6809.md diff --git a/content/notes/03-more-css.md b/content/notes/03-more-css.md index 8ebd3f5de..906f0bea2 100644 --- a/content/notes/03-more-css.md +++ b/content/notes/03-more-css.md @@ -4,9 +4,9 @@ aliases: tags: - cosc203 - lecture -sr-due: 2022-07-31 -sr-interval: 7 -sr-ease: 250 +sr-due: 2022-08-25 +sr-interval: 24 +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) diff --git a/content/notes/06-6809-programming.md b/content/notes/06-6809-programming.md index c839f0771..10afa037d 100644 --- a/content/notes/06-6809-programming.md +++ b/content/notes/06-6809-programming.md @@ -40,7 +40,7 @@ calling routine bsr routine ``` -## Interation +## Iteration use GOTOs ``` diff --git a/content/notes/6809.md b/content/notes/6809.md new file mode 100644 index 000000000..daa64912b --- /dev/null +++ b/content/notes/6809.md @@ -0,0 +1,18 @@ +--- +title: "6809" +aliases: +tags: +- cosc204 +--- + + +# Routines + +# Iteration + +# Input/Output + +# Hello World + +# Assembler + diff --git a/content/notes/comp-210.md b/content/notes/comp-210.md index 4aa549832..434b8d0d7 100644 --- a/content/notes/comp-210.md +++ b/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 diff --git a/content/notes/cryptography.md b/content/notes/cryptography.md index 70f480848..67e8eee16 100644 --- a/content/notes/cryptography.md +++ b/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 +- \ No newline at end of file diff --git a/content/notes/randomness.md b/content/notes/randomness.md index 09c67a2fa..b5e30a715 100644 --- a/content/notes/randomness.md +++ b/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 \ No newline at end of file