  A new method, based on the absorption of very high-energy gamma-rays by the
cosmic infrared background, is proposed to constrain the value of the Hubble
constant. As this value is both fundamental for cosmology and still not very
well measured, it is worth developing such alternative methods. Our lower limit
at the 68% confidence level is H0 > 74 km/s/Mpc, leading, when combined with
the HST results, to H0 ~ 76 km/s/Mpc. Interestingly, this value, which is
significantly higher than the usually considered one, is in exact agreement
with other independent approaches based on baryonic acoustic oscillations and
X-ray measurements. Forthcoming data from the experiments HESS-2 and CTA should
help improving those results. Finally, we briefly mention a plausible
correlation between absorption by the extragalactic background light and the
absence of observation of gamma-ray bursts (GRBs) at very high energies.
