  This work is based on the proposal of a deterministic randomness extractor of
a random Diffie-Hellman element defined over two prime order multiplicative
subgroups of a finite fields $\mathbb{F}_{p^n}$, $G_1$ and $G_2$. We show that
the least significant bits of a random element in $G_1*G_2$, are
indistinguishable from a uniform bit-string of the same length.
  One of the main application of this extractor is to replace the use of hash
functions in pairing by the use of a good deterministic randomness extractor.
