https://homeostasis.scs.carleton.ca/wiki/api.php?action=feedcontributions&feedformat=atom&user=TelidySoma-notes - User contributions [en]2026-05-02T06:09:59ZUser contributionsMediaWiki 1.42.1https://homeostasis.scs.carleton.ca/wiki/index.php?title=SystemsSec_2018W_Lecture_14&diff=21548SystemsSec 2018W Lecture 142018-03-01T04:31:12Z<p>Telidy: /* Notes */</p>
<hr />
<div>==Audio==<br />
<br />
[https://homeostasis.scs.carleton.ca/~soma/systemssec-2018w/lectures/comp4108-2018w-lec14-28Feb2018.m4a Lecture 14 audio.]<br />
<br />
==Notes==<br />
► Many strategies are wrong: If there is one single bug in any major system we use, everything falls apart<br />
<br />
► We can do better, but the way we do things now is not sustainable<br />
<br />
→ Existence proof: Biology<br />
<br />
:1. Everything starts with a random process<br />
<br />
:2. How do biology systems protect itself again adversaries?<br />
<br />
<br />
ANIMALS<br />
*Animals face threats (ie. Falls of cliff, gets eaten)<br />
<br />
*Threats from really small things (huge factor in mortality, ie. humans lifespan doubled because of disease control):<br />
:→ They see the animal as a resource, so why not use it?<br />
:→ Most important defence: Barrier defence<br />
::- Skin<br />
:→ But we can't keep everything out: Basic chemistry<br />
::- Stomach acid to react with what came into your body<br />
::- Digestive enzymes (enzyme: biological catalyst) breaks down proteins<br />
<br />
*Analogies:<br />
::DNA = "Stored code"<br />
:::→ Backbone = "Framework"<br />
<br />
::Proteins = "Running code"<br />
<br />
::T-cells = Has randomized detectors to find bad things. If binded to a regular cell, gets killed<br />
:::→ Auto-immune disease<br />
:::::- T-cell recognizes some behaviour and reacts with it<br />
:::::- To prevent mistakes (ie. autoimmune disease)<br />
::::::○ Only battles when there is evidence cells are dying<br />
<br />
<br />
VIRUSES<br />
*Chunk of DNA/RNA (in between DNA/RNA and proteins) surrounded by proteins<br />
*When comes in contact with cell, injects DNA into cell<br />
:- Overflow cell (cell running malicious code) until it explode, and continue to other cells<br />
:-Cells have vulnerabilities<br />
::□ Viruses targets fact that cells have semi-permeable membranes<br />
:- Defence<br />
::□ Cells have different membranes<br />
<br />
<br />
IMMUNE SYSTEM<br />
*Regular proteins will output certain peptide, immune system checks if its the right one<br />
:- Virus imitates the protein<br />
*Red, hot: Immune system discovered dead cells and investigates<br />
*Incompatible MHC: Organ rejects new organ<br />
<br />
<br />
DIGESTIVE SYSTEM<br />
*When your good bacteria turns bad, fecal transplant<br />
<br />
<br />
The body is not an engineering system: Separation of concern is not there, they are all just cells.</div>Telidyhttps://homeostasis.scs.carleton.ca/wiki/index.php?title=SystemsSec_2018W_Lecture_14&diff=21547SystemsSec 2018W Lecture 142018-03-01T04:28:32Z<p>Telidy: /* Notes */</p>
<hr />
<div>==Audio==<br />
<br />
[https://homeostasis.scs.carleton.ca/~soma/systemssec-2018w/lectures/comp4108-2018w-lec14-28Feb2018.m4a Lecture 14 audio.]<br />
<br />
==Notes==<br />
► Many strategies are wrong: If there is one single bug in any major system we use, everything falls apart<br />
<br />
► We can do better, but the way we do things now is not sustainable<br />
<br />
→ Existence proof: Biology<br />
<br />
:1. Everything starts with a random process<br />
<br />
:2. How do biology systems protect itself again adversaries?<br />
<br />
<br />
ANIMALS<br />
*Animals face threats (ie. Falls of cliff, gets eaten)<br />
<br />
*Threats from really small things (huge factor in mortality, ie. humans lifespan doubled because of disease control):<br />
:→ They see the animal as a resource, so why not use it?<br />
:→ Most important defence: Barrier defence<br />
::- Skin<br />
:→ But we can't keep everything out: Basic chemistry<br />
::- Stomach acid to react with what came into your body<br />
::- Digestive enzymes (enzyme: biological catalyst) breaks down proteins<br />
<br />
*Analogies:<br />
:DNA = "Stored code"<br />
::→ Backbone = "Framework"<br />
<br />
:Proteins = "Running code"<br />
<br />
:T-cells = Has randomized detectors to find bad things. If binded to a regular cell, gets killed<br />
::→ Auto-immune disease<br />
::::- T-cell recognizes some behaviour and reacts with it<br />
::::- To prevent mistakes (ie. autoimmune disease)<br />
:::::○ Only battles when there is evidence cells are dying<br />
<br />
<br />
VIRUSES<br />
:*Chunk of DNA/RNA (in between DNA/RNA and proteins) surrounded by proteins<br />
:*When comes in contact with cell, injects DNA into cell<br />
::- Overflow cell (cell running malicious code) until it explode, and continue to other cells<br />
::-Cells have vulnerabilities<br />
:::□ Viruses targets fact that cells have semi-permeable membranes<br />
::- Defence<br />
:::□ Cells have different membranes<br />
<br />
<br />
IMMUNE SYSTEM<br />
:*Regular proteins will output certain peptide, immune system checks if its the right one<br />
::- Virus imitates the protein<br />
:*Red, hot: Immune system discovered dead cells and investigates<br />
:*Incompatible MHC: Organ rejects new organ<br />
<br />
<br />
DIGESTIVE SYSTEM<br />
:*When your good bacteria turns bad, fecal transplant<br />
<br />
<br />
The body is not an engineering system: Separation of concern is not there, they are all just cells.</div>Telidy