A method for rendering a software program resistant to reverse engineering analysis. At least one first expression in a computational expression or statement of the software program is replaced with a second expression. The first expression being simpler than said second expression and the second expression being based on a value or variables found in said first expression. The second expression produces a value which preserves the value of said first expression. The conversion of the first expression is performed according to a mathematical identity of the form Σi=1k ai ei=E, where ai, are coefficients, ei, are bitwise expressions, whether simple or complex, and E is said first expression.