Volume 3 - Issue 1 - 2
Efficient Certificateless Online/Offline Signature with tight security
- 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
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, Tight Reduction.
Abstract
Since public key cryptography is usually build using computationally expensive operation, it has
been out of reach for resource constrained and low power devices. Today there are a large number of
low power devices in use and they perform complex tasks. There is need for light weight cryptography
having high security and low communication overhead. Online/Offline schemes are well suited
for this purpose since they allow the use of public key cryptosystems in these low power devices.
Many cryptosystems that are efficient in terms of number of computational steps may be inefficient
if we consider the size of keys that must be used to achieve a acceptable level of security. Especially
cryptosystems that have a loose security proof may work with large keys, this increases the communication
overhead. In this paper, we show a view of the how Certificateless schemes are constructed.
Then, we present a Certificateless Online/Offline Signature (CLOOS) Scheme and give a tight security
reduction to the Gap Diffie-Hellman problem in the random oracle model. Even though other
schemes exist that are are constructed using less number computational steps, if we take into account
the size of keys our scheme will be more efficient. Thus, our scheme is light weight and has a low
communication overhead.