70004 & 70046: added friday ADSD lecture and advanced security

Author: OliverKillane

70004 - Advanced Computer Security/1975 Design Principles.md

@@ -8,4 +8,3 @@ Covers the evolution of basic computer security principles.
 > - Earl Boebert
 ## Commentary
 - *Defence in depth* seems often overlooked (having multiple layers of defences in a system), having *Compromise recording* seems to be in this vein also.
-- 

70004 - Advanced Computer Security/Accountability.md

@@ -0,0 +1,4 @@
+## Definition
+Being able to determine the attacker or [[Principle]].
+- Audit trails and logs, even in security failure there is a need to detect in order to react, and investigate after is system is re-secured.
+- Secure timestamping (e.g. using OS, or network, attacker may attempt to damage integrity of logs)

70004 - Advanced Computer Security/Availability.md

@@ -0,0 +1,5 @@
+## Definition
+The uptime of a system.
+- Maximum traffic, measured historically and guaranteed by SLAs with providers.
+- Using redundancy to reduce possible single points of failure (e.g. replicating databases, auto-scaling for load)
+Many attacks are [[Denial of Service]].

70004 - Advanced Computer Security/Defence in Depth.md

@@ -0,0 +1,8 @@
+## Definition
+Using multiple layers of security, and monitoring to remove single points of failure for security.
+## Example
+### Account monitoring
+- Using password authentication for accounts.
+- Monitor number of denied logins, conservatively blocking clients that fail to log in repeatedly.
+- Monitor logins for suspicious activity, and block judiciously.
+- Monitor suspected compromised accounts.

70004 - Advanced Computer Security/Denial of Service.md

@@ -0,0 +1,2 @@
+## Definition
+Overwhelming public services with large volumes of illegitimate traffic to prevent them servicing legitimate traffic.

70004 - Advanced Computer Security/Non-Reputation.md

@@ -0,0 +1,6 @@
+## Definition
+> *Alice wants to prove to Trent she did communicate with Bob*
+
+Collecting undeniable evidence of some transaction.
+- receipts, digitally signed logs
+- helps with [[Accountability]], and for investigations (e.g. determining if a transaction was fraudulent, or valid based on an untrusted customer's testimony).