The problem of securing XML databases is rapidly gaining interest for both academic and industrial research. It becomes even more challenging when XML data are managed and delivered according to the P2P paradigm, as malicious attacks could take advantage from the totally-decentralized and untrusted nature of P2P networks. Starting from these considerations, in this paper we propose the guidelines of a distributed framework for supporting (i) secure fragmentation of XML documents into P2P XML databases by means of lightweight XPath-based identifiers, and (ii) the creation of trusted groups of peers by means of self-certifying? XPath links that exploit the benefits of well-known fingerprinting techniques.