Volume 2 - Issue 3 – 4
Efficient Certificateless Online/Offline Signature
- S. Sharmila Deva Selvi
Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
sharmila@cse.iitm.ac.in
- S. Sree Vivek
Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
svivek@cse.iitm.ac.in
- Vivek Krishna Pradhan
Indian Institute of Science Eduction and Research, Pune, Maharashtra, India
vivek.k.pradhan@gmail.com
- C. Pandu Rangan
Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
prangan@cse.iitm.ac.in
Keywords: certificateless cryptography, online/offline computation, signature, provable security, random oracle model.
Abstract
Public key cryptography usually is computationally more expensive than symmetric key systems.
Due to this low power or resource constrained devices cannot make use of public key cryptosystems
easily. There is a need for high security in these devices since many of these devices perform complex
tasks which includes interaction with third party cloud infrastructures. These cloud infrastructures
are not trusted entities. Hence there is need for light weight public key cryptography which are secure
against these cloud administrators. The trusted entity in certificateless schemes cannot compromise
the security of the users. Online/offline have two parts, first the computationally heavy part(offline)
of the cryptosystem and then the main “online” algorithm for use on resource constrained devices.
The heavy computations are done in the offline phase on a more powerful device. Hence, Certificate-
less online/offline schemes are perfect for low power devices interacting with clouds. In this paper,
we present a certificateless online/offline signature scheme. This scheme is the most efficient certifi-
cateless signature scheme in existence and also has the added advantage of being online/offline. The
scheme is proven secure in the random oracle model.