Encryption schemes and key exchange protocols in the certificateless setting
Lippold, Georg (2010) Encryption schemes and key exchange protocols in the certificateless setting. PhD thesis, Queensland University of Technology.

Georg Lippold Thesis
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Abstract
The contributions of this thesis fall into three areas of certificateless cryptography. The first area is encryption, where we propose new constructions for both identitybased and certificateless cryptography. We construct an noutof n group encryption scheme for identitybased cryptography that does not require any special means to generate the keys of the trusted authorities that are participating. We also introduce a new security definition for chosen ciphertext secure multikey encryption. We prove that our construction is secure as long as at least one authority is uncompromised, and show that the existing constructions for chosen ciphertext security from identitybased encryption also hold in the group encryption case. We then consider certificateless encryption as the special case of 2outof2 group encryption and give constructions for highly efficient certificateless schemes in the standard model. Among these is the first construction of a latticebased certificateless encryption scheme. Our next contribution is a highly efficient certificateless key encapsulation mechanism (KEM), that we prove secure in the standard model. We introduce a new way of proving the security of certificateless schemes based that are based on identitybased schemes. We leave the identitybased part of the proof intact, and just extend it to cover the part that is introduced by the certificateless scheme. We show that our construction is more efficient than any instanciation of generic constructions for certificateless key encapsulation in the standard model. The third area where the thesis contributes to the advancement of certificateless cryptography is key agreement. Swanson showed that many certificateless key agreement schemes are insecure if considered in a reasonable security model. We propose the first provably secure certificateless key agreement schemes in the strongest model for certificateless key agreement. We extend Swanson's definition for certificateless key agreement and give more power to the adversary. Our new schemes are secure as long as each party has at least one uncompromised secret. Our first construction is in the random oracle model and gives the adversary slightly more capabilities than our second construction in the standard model. Interestingly, our standard model construction is as efficient as the random oracle model construction.
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ID Code:  41697 

Item Type:  QUT Thesis (PhD) 
Supervisor:  Boyd, Colin & Gonzalez Nieto, Juan 
Keywords:  certificateless encryption, certificateless key encapsulation, certificateless key agreement, security models, INDCPA, INDCCA2, generic conversion, IDbased, standard model, random oracle model, bilinear pairings, lattices, trapdoor algorithms 
Divisions:  Past > QUT Faculties & Divisions > Faculty of Science and Technology Past > Institutes > Information Security Institute 
Institution:  Queensland University of Technology 
Deposited On:  16 May 2011 05:22 
Last Modified:  28 Oct 2011 20:01 
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