It is commonly known that there is a trade off between the security of the systems based on biometric solutions and the privacy of the biometric data itself. In particular, the technologies behind practical privacy preserving algorithms and protocols belong to several different disciplines including signal processing, cryptography, information theory, each of which with a long standing tradition of theoretical and practical studies. At the same time, only few is known about their joint use, both at a theoretical and a practical level, the separation-paradigm being by far the most popular approach. The main goal of this thesis is to provide privacy preserving solutions to handle biometric samples avoiding the leakage of information that is intrinsic in the existing approaches and guaranteeing the privacy of the users.