A new trust model will be developed for grid metacomputing over multiple administrative domains. The GridSec enhances grid operations with seamless security, assured privacy, data integrity, confidentiality, and optimized resource allocations. Distributed micro firewalls and intrusion repelling libraries for protecting grid resources will be generated as a part of this project. The new security system will be designed to adjust itself dynamically with changing threat patterns and network conditions. Fine-grain resource-access control at the file, device, and storage levels will be designed to enhanced the trusted aspect of the system. The results of this project will benefits all grid applications and offers protection of shared grid resources. The eventual construction of a production grid platform dedicated for global emergency response and crisis management is one of the project's goals. This work integrates advanced security research with higher education. The project enhances Internet and grid security, reduces the vulnerability of our society, and protects the global economy as a whole. The broader impacts are far reaching in science, education, business, and governments.