There are multiple methods of generating keys. These include, but are not limited to, using Bootgen, customized key files, OpenSSL and hardware security modules (HSMs). This tutorial covers methods using bootgen. The Bootgen created files can be used as templates for creating files containing user-specified keys from the other key sources.
The creation of keys using Bootgen commands requires the generation and modification of the BIF files. The key generation section of this tutorial creates these BIF files “by hand” using a text editor. The next section, building your boot image demonstrates how to create these BIF files using the Bootgen GUI (create Boot Image Wizard).