Integrated Dell Remote Access Controller 9 Version 3.30.30.30 User's Guide

Acceptable file formats

The Secure Boot policy contains only one key in PK, but multiple keys may reside in KEK. Ideally, either the platform manufacturer or platform owner maintains the private key corresponding to the public PK. Third parties (such as OS providers and device providers) maintain the private keys corresponding to the public keys in KEK. In this way, platform owners or third parties may add or remove entries in the db or dbx of a specific system.

The Secure Boot policy uses db and dbx to authorize pre-boot image file execution. For an image file to get executed, it must associate with a key or hash value in db, and not associate with a key or hash value in dbx. Any attempts to update the contents of db or dbx must be signed by a private PK or KEK. Any attempts to update the contents of PK or KEK must be signed by a private PK.

Table 1. Acceptable file formatsAcceptable file formats

Policy Component	Acceptable File Formats	Acceptable File Extensions	Max records allowed
PK	X.509 Certificate (binary DER format only)	.cer .der .crt	One
KEK	X.509 Certificate (binary DER format only) Public Key Store	.cer .der .crt .pbk	More than one
DB and DBX	X.509 Certificate (binary DER format only) EFI image (system BIOS will calculate and import image digest)	.cer .der .crt .efi	More than one

The Secure Boot Settings feature can be accessed by clicking System Security under System BIOS Settings. To go to System BIOS Settings, press F2 when the company logo is displayed during POST.

When the Secure Boot Policy is configured as Custom, it inherits the standard certificates and image digests loaded in the system by default, which you can modify. Secure Boot Policy configured as Custom allows you to perform operations such as View, Export, Import, Delete, Delete All, Reset, and Reset All. Using these operations, you can configure the Secure Boot Policies.

Configuring the Secure Boot Policy to Custom enables the options to manage the certificate store by using various actions such as Export, Import, Delete, Delete All, Reset, and Rest All on PK, KEK, DB, and DBX. You can select the policy (PK / KEK / DB / DBX) on which you want to make the change and perform appropriate actions by clicking the respective link. Each section will have links to perform the Import, Export, Delete, and Reset operations. Links are enabled based on what is applicable, which depends on the configuration at the point of time. Delete All and Reset All are the operations that have impact on all the policies. Delete All deletes all the certificates and image digests in the Custom policy, and Rest All restores all the certificates and image digests from Standard or Default certificate store.