The invention relates to a virtual machine. The virtual machine is set to recognize, in addition to a set of conventional bytecodes, at least one secure bytecode functionally equivalent to one of the conventional bytecodes. It is set to process secure bytecodes with increased security, while it is set to process conventional bytecodes with increased speed. The invention also relates to a computing device comprising such a virtual machine, to a procedure for generating bytecode executable by such a virtual machine, and to an applet development tool comprising such procedure.