Methods are provided for securely loading software objects into an electronic control unit. The methods include receiving a first software object comprising a second level public key certificate, a first encryption signature and a first set of software. Once the first software object is received, validating the first second level public key is validated with the embedded root public key, the first encryption signature with the first second level public key certificate, and the first set of software with the first encryption signature. When the first set of software is valid, then the first second level public key certificate and the first set of software are stored to non-volatile memory. Once stored, a consecutive software object is received comprising only a consecutive encryption signature and a consecutive set of software from the programming source. The consecutive encryption signature is validated with the stored second level public key certificate, and the consecutive set of software is validated with the consecutive encryption signature.