// it consists of a 128 bit hex value (32 hex chars) and exactly
// one '-' followed by a 32-bit number.
// This special case addresses randomly-generated ETags generated
// by the MinIO server when running in non-compat mode. These
// random ETags are not encrypt.
//
// Calling DecryptETag with a non-randomly generated ETag will
// fail.
func DecryptETag(key crypto.ObjectKey, object ObjectInfo) (string, error) {