Amazon S3 is a very secure storage service. Some of the main security

mechanisms available in Amazon S3 are as follows:

1. Access: When we create a bucket or an object, only the owner get the

access to the bucket and objects.

2. Authentication: Amazon S3 also support user authentication to

control who has access to a specific object or bucket.

3. Access Control List: We can create Access Control Lists (ACL) to

provide selective permissions to users and groups.

4. HTTPS: Amazon S3 also supports HTTPS protocol to securely

upload and download data from cloud.

5. Encryption: We can also use Server Side Encryption (SSE) in

Amazon S3 to encrypt data

https://aws.amazon.com/s3/security/