Update README.md (#18)

Added more details into Security section per expected layout

Author: dzilbermanvmw

README.md

@@ -89,12 +89,34 @@ Please note that thise are estimated costs for reference only. The actual cost m
 
 ## Deployment Documentation
 
-Please see detailed Implementation Guides here: 
+Please see detailed guidance Implementation Guides here: 
 - [English](https://aws-solutions-library-samples.github.io/ai-ml/asynchronous-image-generation-with-stable-diffusion-on-aws.html)
 - [Chinese 简体中文 ](https://aws-solutions-library-samples.github.io/ai-ml/asynchronous-image-generation-with-stable-diffusion-on-aws-zh.html)
 
 ## Security
 
+When you build systems on AWS infrastructure, security responsibilities are shared between you and AWS. This [shared responsibility model](https://aws.amazon.com/compliance/shared-responsibility-model/) reduces your operational burden because AWS operates, manages, and
+controls the components, including host operating systems, the virtualization layer, and the physical security of the facilities in
+which the services operate. For more information about AWS security, visit [AWS Cloud Security](http://aws.amazon.com/security/).
+
+### IAM Roles
+AWS Identity and Access Management (IAM) roles allow AWS customers to assign granular access policies and permissions to AWS services and users in the cloud.
+
+This guidance creates separate IAM roles and grants permissions for the following components:
+1. Amazon EKS cluster, including
+  * Creating and operating the cluster
+  * Compute node groups
+  * Nodes created by Karpenter
+  * Pods running in the cluster, including
+    *      Karpenter
+    *      KEDA
+    *      Fluent Bit
+    *      Stable Diffusion runtimes
+2. AWS Lambda functions
+3. Amazon API Gateway
+
+This guidance uses IAM roles for internal user access control, following the principle of least privilege, ensuring that each component can only access authorized components and maintaining application workload isolation.
+
 See [CONTRIBUTING](CONTRIBUTING.md#security-issue-notifications) for more information.
 
 ## License