AWS EC2 DB data encyption

We use S3 and an Oracle DB in EC2. We send encrypted data from our company to AWS s3 and then loading this data( after decryption) to Oracle installed in Ec2. Now, we maintan KMS managed key AWS and need to encrypt the data before loading to Oracle. Is there anyway to decrypt data from S3 and encrypt using KMS key before loading to oracle?

Thanks, Baskar.S