Bucket Policies: Restrict access using the principle of least privilege.

Encryption: Always enable SSE for data at rest. Use SSE-S3 or SSE-KMS based on your security and compliance requirements.

Access Logging: Enable logging to track access and monitor for unauthorized activities.

Versioning: Enable versioning to protect against accidental deletion or overwrite.

IAM: Use IAM roles and policies to control who can create, modify, or delete S3 resources.

Monitoring: Use Amazon CloudWatch for monitoring S3 access patterns and set up alerts for unusual activities.

Regular Audits: Conduct regular security audits and reviews of your S3 configurations.