Cryptanalysis of a technique to transform discrete logarithm based
  cryptosystems into identity-based cryptosystems

by Qiang Tang and Chris J. Mitchell

Abstract:

In this paper we analyse a technique designed to transform any
discrete logarithm based cryptosystem into an identity-based
cryptosystem. The transformation method is claimed to be efficient
and secure and to eliminate the need to invent new identity-based
cryptosystems. However, we show that the identity-based
cryptosystem created by the proposed transformation method suffers
from a number of security and efficiency problems.