SecurityPkg\Tcg\Opal. It includes a feature named PSID. PSID is a hard driver specific key which is used to revert to factory default mode. This PSID value should be kept as secret. Current EDKII OPAL driver does not clear PSID in memory after use. The secret value is left in stack, or global variable memory without clear. Technically, a malicious program may search memory and find out the PSID in memory, if user inputs the PSID value in BIOS.
ZeroMem()to clear PSID in memory after it is used.
ZeroMem()to clear secret in memory after it is used.