Criptografía Basada en Identidad

Abstract

In this thesis, it is shown how the use of bilinear pairings leads to cryptosystems that provide new functionality. The Tripartite Diffie Hellman Protocol is implemented; this is a protocol for the establishment ok keys between parties who have not had a previous contact, using an insecure channel in an anonymous (unauthenticated) way. This protocol was named after its creators, who proposed it in 1976 [11]. Generally, the Diffie-Hellman protocol It is used to exchange symmetric keys that will be used as an example for encrypting a session (i.e. to establish the session key). Although this is an unauthenticated protocol, it provides the foundation for several authenticated protocols . The security of this protocol resides in the extreme difficulty (conjectured, not proven) to compute discrete logarithms over finite fields. The version of the Diffie-Hellman protocol implemented in this thesis was developed by Joux [20] and it uses bilinear pairings and elliptic curves, allowing three participants to share keys in a single step comunication. For the developed implementation, GMP libraries were used for handling large numbers, while PBC libray was used to manage bilinear pairings.