  This paper attempts to provide an estimation of the prevalence of hostile
extraterrestrial civilizations through an extrapolation of the probability that
we, as the human civilization, would attack or invade an inhabited exoplanet
once we become a Type-1 civilization in the Kardashev Scale capable of nearby
interstellar travel. The estimation is based on the world's history of
invasions in the last century, the military capabilities of the countries
involved, and the global growth rate of energy consumption. Upper limits of
standard deviations are used in order to obtain the estimated probability of
extraterrestrial invasion by a civilization whose planet we send a message to.
Results show that such probability is two orders of magnitude lower than the
impact probability of a planet-killer asteroid. These findings could serve as a
starting point for an international debate about sending the first serious
interstellar radio messages to nearby potentially habitable planets.
