在生成加密的 bootable image 中有一个步骤 Step 3: Copy the “cst” executable, “crts” folder, and “keys” folder from “<cst_installation_dir>” to the same folder that holds Elftosb utility executable.
The cst is a command-line host program used to generate certificates, image signatures, and encrypt
images for i.MX MCU Boot ROM.
NOTE
These applications are released as part of Flashloader release package available on www.nxp.com/KBOOT. They are available in the <install_dir>/bin/Tools folder of the release package