We report on chaotic polarization fluctuations generated from a free-running vertical-cavity surface-emitting laser, and investigate in details the VCSEL dynamics and its potential application. We provide new experimental evidences of asymmetrical behaviour of VCSEL polarization dynamics, and show that considering a slight misalignment of the anisotropies of the laser cavity allows to reproduce these dynamics numerically. Finally, we propose a simple scheme for random bit generation exploiting polarization chaos , and experimentally demonstrate a 100 Gbps random generation rate.