In the AWS shared responsibility model:

Customer Responsibility (Security IN the Cloud):

• Perform client-side data encryption - Customers are responsible for encrypting their data before sending it to AWS
• Configure IAM credentials - Customers manage their own IAM users, groups, roles, and policies

AWS Responsibility (Security OF the Cloud):

• Establish the global infrastructure (AWS manages the physical infrastructure)
• Secure edge locations (AWS manages security of edge locations and CloudFront)
• Patch Amazon RDS DB instances (AWS manages patching of the underlying RDS service)

The shared responsibility model divides security responsibilities where AWS is responsible for the security OF the cloud (infrastructure), while customers are responsible for security IN the cloud (their data, applications, and configurations).