Young people are increasingly turning to virtual private networks (VPNs) to anonymise their free sharing of music and movies, a new study has suggested.
Sweden's Lund University indicated that there had been a 40% rise in the number of 15 to 25-year-olds using such services since 2009.
Many believe a clampdown on piracy is behind their rise in popularity.
The Pirate Bay has advised visitors to make use of VPNs. It would be illegal to do so to download pirated files.