A secure boot mechanism is described. The secure boot mechanism can operate in environments not originally designed to support such a mechanism. Downstream boot components can be executed from an encrypted boot partition. A first stage boot loader (FSBL) can load a second stage boot loader (SSBL) from an encrypted disk partition. The FSBL can decrypt and load the SSBL. The FSBL can intercept all I/O initiated by the SSBL so that the SSBL can transparently operate on an encrypted disk partition as though the encrypted disk were unencrypted.