During execution of BIOS at an information handling system, a processor communicates with the storage controller via a command line protocol (CLP) communications channel. Via the channel, the processor obtains identification information for storage devices associated with the storage controller. The processor communicates the identification information to a key management client, which obtains encryption keys based on the identification information from a key management server. The processor receives the encryption keys, and communicates them to the storage controller via the CLP communications channel. The CLP communications channel thus provides a convenient and flexible interface for communication of security information prior to execution of an operating system.