The Virtual Organization Membership Service (VOMS) was originally developed in the framework of EDG and DataTAG collaborations to solve the problems of granting users authorization to access the resources at VO level, providing support for group membership and roles. It is now mainteined within the EU project Enabling Grid for E-SciencE (EGEE).
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The Virtual Organization Membership Service (VOMS) is an attribute authority
which serves as central repository for VO user authorization information,
providing support for sorting users into group hierarchies, keeping track of
their roles and other attributes in order to issue trusted attribute
certificates and SAML assertions used in the Grid environment for
authorization purposes.