The majority of current security architectures for grid systems use public key infrastructure (PKI) to authenticate identities of grid members and to secure resource allocation to these members. Identity-based cryptography (IBC) has some attractive properties which seem to align well with the demands of grid computing. This paper presents a comprehensive investigation of the use of identity-based techniques to provide an alternative grid security architecture. We propose a customised identity-based key agreement protocol which fits nicely with the Grid Security Infrastructure (GSI) and provides a more lightweight secure job submission environment for grid users. Single sign-on and delegation services are also supported in a very natural way in our identity-based architecture.