1. A computer system for providing tamper-resistant executable software code, comprising: an input/output unit for transferring commands to the computer from an operator; a processor for responding to commands from the processor; a memory having stored therein a computer program product, stored on a tangible computer memory media, operable on the processor, the computer program product comprising a set of instructions that, when executed by the processor, cause the computer to provide tamper-resistant executable software code by performing the operations of: formatting all instructions in a code segment to use operand indirect addressing so that each instruction comprises an opcode and indirect table index values, storing operand data in one or more index tables associated with the code segment, encoding the code segment by rearranging its instructions, and sequentially storing next sequential instruction index values in a jump table so that the encoded code segment can be decoded during execution through use of the jump table.