importance of secure application design
-cost increases as the flaw identified in the later process of SDLC
	*0,*1,*6,*15,100*
-best to be done in the design phase
-developer will be forced to write a better code
-so we can mitigate as much as treat as can

various secure design principles
-SecurityThroughObsecurity-make it unknown or make the flaw unknown
-secure the weakest link-usually attacker will find end point instead of trying to decrypt
-use least privilege principles
-secure by default-by default password aging n complexity should be enabled
-fail securely-means when fail don't expose error info
-apply defense in depth-apply check to the entire flow
-do not trust user input
-reduce attack surface-reduce entry points as much as can
-enable auditing and logging
-seperation of duties-example system administrator should not be allowed as super-priv user
-fix security issues correctly-check new code introduced for not producing new flaw
-protect sensitive data-use the best encryption method
-exception handling
-secure memory management-check for buffer over flow-check length before pushing in
-protect memory or storage secrets-encryt secrets to avoid being dumped in crash dump,scrub before deletion
-fault tolerance-system should continue to perform despite errors
-fault detection-at the same time, should inform relevant party about detection-at
-fault removal-during design phase
-fault avoidance-during development
-loose coupling- avoid dependency
-high cohesion-a code that can perform many things based on parameter changes, reduce code and complexity
-change management n version control-

threat modeling
	-once we are done with this, we will be able to see the
		system in a very simple and secure manner !
-identify,analyze and mitigate the threats
-performed at design phase
-iterative process
-should be able to produce all flaws in the end

thread modeling process
	1. identify security objectives
		-questionnaires
	2.create an application overview
		-draw the end to end deployment architecture
		-identify various user roles-who can do what
		-identify use case scenarious-create,read,update,delete jobs
		-identify technologies-os,ws,ds,languages
		-identify application security mechanisms
	3.decompose the application
		-prepare the document threat model information
		-identify the external dependencies
		-identify the entry points
		-identify the assets-folders,user information such as id, NRIC
		-identify the trust levels
		-define trust levels to entry points
		-define trust levels to assets
		-check if DFD is accurately designed based on the above elements
		-once redefined, we can find all possible ways of attacker to interrupt
		-now all threat path can be redefined
	4.identify threats
		-different possible categories
		-categorize the threats
		-use STRIDE
			-categorizes based on goals n purpose of attack
		-document the threat
		-rate the threats
		-use DREAD model

	5. identify vulnerabilities

secure application architecture design
-use tiers in the entire app design
-usually web, application, database