The Opal Storage Specification is a set of specifications for features of data storage devices (such as hard disk drives and solid state drives) that enhance their security.
For example, it defines a way of encrypting the stored data so that an unauthorized person who gains possession of the device cannot see the data.
That is, it is a specification for self-encrypting drives (SED).
The specification is published by the Trusted Computing Group Storage Workgroup.
The Opal SSC (Security Subsystem Class) is an implementation profile for Storage Devices built to: The Opal SSC encompasses these functions: Radboud University researchers indicated in November 2018 that some hardware-encrypted SSDs, including some Opal implementations, had security vulnerabilities.