Correct answer - "'x-amz-server-side-encryption': 'AES256'" : To request server-side encryption
using the object creation REST APIs, provide the , x-amz-server-side-encryption request header.
Amazon S3 server-side encryption uses one of the strongest block ciphers available, 256-bit
Advanced Encryption Standard (AES-256), to encrypt your data.
"'x-amz-server-side-encryption': 'SSE-S3'" - SSE-S3 (Amazon S3-Managed Keys) is an option
available but not a header value
"'x-amz-server-side-encryption': 'SSE-KMS'" - SSE-KMS (AWS KMS-Managed Keys) is an option
available but not a header value. A valid value would be 'aws:kms'
"'x-amz-server-side-encryption': 'aws:kms'" - This is a valid header value and you can use if you
need more control over your keys like create, rotating, disabling them otherwise if you wish to
let AWS S3 manage your keys just stick with SSE-S3