Grid computing provides consistent, inexpensive access to computational resources (supercomputers, storage systems, data sources, instruments, and people) regardless of their physical location or access point. As such, The Grid provides a single, unified resource for solving large-scale compute and data intensive computing applications. The survey of distributed system security, with applications for the grid security infrastructure, begins with an overview of grid computing, security and grid security infrastructure (GSI).For user authentication, delegation and single sign –on, the OGSA (Open Grid Services Architecture) uses the GSI (Grid Security Infrastructure)protocol. The goal of this survey is to increase the awareness of security issues in Grid Computing.