1. A computing device which selectively operates in a non-privileged mode and a privileged mode, said computing device comprising: a trusted data section configured to store an authentication routine which includes a plurality of immediate-operand instructions wherein each of said plurality of immediate operand instructions has an operand configured to convey a portion of a password; a first control section configured to grant read access to said immediate-operand instruction in response to an instruction fetch addressed to said trusted data section; a non-trusted data section configured to store a password guess; and a second control section, configured as a physical circuit, coupled to said trusted and non-trusted data sections and configured to identify when a predetermined relationship exists between all of said plurality of immediate-operand instructions and said password guess and to signal said privileged mode of operation in response to identifying said predetermined relationship.