  It is shown that stringy matter near the event horizon of a Schwarzschild
black hole exhibits chaotic behavior (the spreading effect) which can be
characterized by the Kolmogorov-Sinai entropy. It is found that the
Kolmogorov-Sinai entropy of a spreading string equals to the half of the
inverse gravitational radius of the black hole. But the KS entropy is the same
for all objects collapsing into the black hole. The nature of this universality
is that the KS entropy possesses the main property of temperature: it is the
same for all bodies in thermal equilibrium with the black hole. The
Kolmogorov-Sinai entropy measures the rate at which information about the
string is lost as it spreads over the horizon. It is argued that it is the
maximum rate allowed by quantum theory. A possible relation between the
Kolmogorov-Sinai and Bekenstein-Hawking entropies is discussed.
