Defined in github.com/aws/aws-sdk-go/service/s3/api.go
Specifies the customer-provided encryption key for Amazon S3 to use in encrypting data. This value is used to store the object and then it is discarded; Amazon does not store the encryption key. The key must be appropriate for use with the algorithm specified in the x-amz-server-side-encryption-customer-algorithm header. This must be the same encryption key specified in the initiate multipart upload request.