Securely executing instructions of software on a computerized device by accessing a software of a computerized device, wherein the software includes a plurality of instructions and respective reference message authentication codes (MACs), generating a cryptographic key based at least in part on a key derivation function, wherein arguments of the key derivation function are based at least in part on a unique identifier of the computerized device and a value extended from a measurement of a content of the software of an extension mechanism of a platform configuration register of the computerized device, verifying an instruction of the plurality of instructions of the software based at least in part on the cryptographic key and a reference MAC of the respective reference MACs, and in response to verifying the instruction of the plurality of instructions of the software, executing the instruction.