1. A computer implemented method for preventing hostile attacks against a computer program, comprising: providing a processor executing instructions for running a preposition in a secure computing environment separate from an original call site within native program code of the computer program, said preposition comprising an IF antecedent having a TRUE consequence and a FALSE consequence; said processor providing a different response for each consequence; and said computer program executing the native program code in a computing environment that is controlled by an attacker; said native program code providing a check value to a script in said secure computing environment and waiting for said script to return a value that is expected upon proper completion of the script; and repeatedly providing a check value to said script in said secure computing environment during execution of the native program code with a series of calls to the script in said secure computing environment, where the check value is repeatedly changed by the native program code and where a different expected value is returned after each call; and wherein a hostile attack is detected when the check value returned by the call is not the expected value.