In public key cryptography, due to the random nature of each user’s public key, it is necessary to make a link between the public key and the identity of owner of the corresponding private key. In a traditional public key infrastructure (PKI) this link is accomnplished by a digital certificate. Complexity of certificate management process is the main challenge in PKI. To overcome to this challenge ID-based public key cryptography has been proposed by Shamir in 1984. It’s main concept is that each user’s public key is generated from his/her identification information such as name, email address. IP address, etc. The corresponding private key is generated by a private key generator (PKG) using a secure master key, and transmitted to the user via a secure channel. In 1984 Shamir proposed the first ID-based signature scheme but the invention of an efficient ID-based encryption scheme realised in 2001 when Boneh and Franklin proposed the first scheme using bilinear pairings, namely Weil and Tate pairing which uses elliptic curves. By their work research in this area accelerated. In this thesis, we focus on “ID-based cryptosystems which use bilinear pairings”. After an introduction of the basis of “elliptic curves” and “bilinear pairings”, some ID-based cryptoprimitives such as plain signature schemes, ring signature and proxy signature schemes are reviewed and an ID-based undeniable digital signature scheme and an ID-base proxy signature scheme and a “two-party identity-based authenticated key agreement protocol” is proposed.