Create a new S3 bucket with server-side encryption using customer-provided keys (SSE-C), then copy the existing objects to this new bucket while specifying SSE-C.

Create a new S3 bucket with server-side encryption using Amazon S3 managed keys (SSE-S3), and utilize S3 Batch Operations to copy the existing objects to this new bucket, specifying SSE-S3.

Utilize AWS CloudHSM to store the encryption keys, create a new S3 bucket, and use S3 Batch Operations to copy the existing objects to this new bucket, encrypting the objects with keys from CloudHSM.

Implement the S3 Intelligent-Tiering storage class for the S3 bucket and create an S3 Intelligent-Tiering archive configuration to transition objects not accessed for 90 days to S3 Glacier Deep Archive.