  The cosmic infrared background (CIB) is gravitationally lensed. A
quadratic-estimator technique that is inherited from lensing analyses of the
cosmic microwave background (CMB) can be applied to detect the CIB lensing
effects. However, the CIB fluctuations are intrinsically strongly non-Gaussian,
making CIB lensing reconstruction highly biased. We perform numerical
simulations to estimate the intrinsic non-Gaussianity and establish a
cross-correlation approach to precisely extract the CIB lensing signal from raw
data. We apply this technique to CIB data from the Planck satellite and
cross-correlate the resulting lensing estimate with the CIB data, galaxy number
counts and the CMB lensing potential. We detect an excess that is consistent
with a lensing contribution at $>4\sigma$.
