A system and method for securely flashing a controller, where the controller includes at least one main processor and at least one secondary processor, and where the processing duties are distributed between the processors. A programming tool provides a content file to be flashed and a digital signature to the controller. The controller calculates a hash value of the content file, decrypts the digital signature using a public key to generate a decrypted hash value, compares the decrypted hash value to the calculated hash value, and determines that the content file is valid if the decrypted hash code matches the calculated hash value, where one or more of the steps of calculating the hash value, decrypting the digital signature, comparing the decrypted hash value to the calculated hash value and determining that the content file is valid, is performed by the main processor for the secondary processor.