Numerical evaluation of the average number of successive guesses

This work has been inspired by problems addressed in the field of computer security, where the attacking of, e.g., password systems is an important issue. In [2] Lundin etal. discuss measures related to the number of guesses or attempts a supposed attacker needs for revealing information. Here several numerical approaches are discussed for evaluating the average number of successive guesses required for correctly guessing the value of a string of independent and identically-distributed random variables. The guessing strategy used is guessing strings in decreasing order of probability [1].