  Computational grids are believed to be the ultimate framework to meet the
growing computational needs of the scientific community. Here, the processing
power of geographically distributed resources working under different
ownerships, having their own access policy, cost structure and the likes, is
logically coupled to make them perform as a unified resource. The continuous
increase of availability of high-bandwidth communication as well as powerful
computers built of low-cost components further enhance chances of computational
grids becoming a reality. However, the question of grid security remains one of
the important open research issues. Here, we present some novel ideas about how
to implement grid security, without appreciable performance degradation in
grids. A suitable alternative to the computationally expensive encryption is
suggested, which uses a key for message authentication. Methods of secure
transfer and exchange of the required key(s) are also discussed.
