'$RCSfile: eml-access.xsd,v $' Copyright: 1997-2002 Regents of the University of California, University of New Mexico, and Arizona State University Sponsors: National Center for Ecological Analysis and Synthesis and Partnership for Interdisciplinary Studies of Coastal Oceans, University of California Santa Barbara Long-Term Ecological Research Network Office, University of New Mexico Center for Environmental Studies, Arizona State University Other funding: National Science Foundation (see README for details) The David and Lucile Packard Foundation For Details: http://knb.ecoinformatics.org/ '$Author: jones $' '$Date: 2002-12-06 22:23:42 $' '$Revision: 1.64 $' This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA eml-access

The eml-access module describes the level of access that is to be granted or denied to a resource or a subset of a resource for a particular user or group of users. A single eml-access document may be used to express access control for many resources, or for a given resource (e.g., a dataset or citation ). The eml-access module represents a list of resources to be controlled in the context of a particular authentication system. That is, the authentication system determines the set of principals (users + groups) that can be used, and the membership of users in groups. The rules set in this module will determine the level of access to a resource for the defined users and groups. In EML, there are two mechanisms for including access control information via the eml-access module. 1) Each top-level resource module (eml-dataset, eml-literature, eml-software, and eml-protocol) include an optional <access> element directly inline in the document. This is used to define access control at the resource level scope. 2) Finer grained access control may be applied to a subset of a resource via the <addtionalMetadata> element in the eml module. An access control document may be defined, or referenced, from this location, and the <describes> element is used to point to the subset of the resource that is to be controlled via its "id" attribute. Applications that process EML documents must implement the access control rules from both mechanisms. Note that, although access control may be bound to any element with an "id" attribute, the processing involved may be very costly. For instance, it would not be recommended to apply access control to a column of a data file (eml-attribute), since every read/write operation on that column may not proceed until access is verified. The eml-access module, like other modules, may be "referenced" via the <references> tag. This allows an access control document to be described once, and then used as a reference in other locations within the EML document via it's ID.

all data where controlling user access to the dataset is an issue yes Access control rules The rules defined in this element will determine the level of access to a resource for the defined users and groups. The access element contains a list of rules that define the level of access for a given resource, be it a dataset or another metadata document. Because the access element is declared to be of complex type 'AccessType', an instance must contain the elements defined for accessType. See the description of individual elements defined in AccessType to review each component element's rules. Access control rules The rules defined in this element will determine the level of access to a resource for the defined users and groups. The access element contains a list of rules that define the level of access for a given resource, either a dataset or another metadata document. The access element must contain the elements defined in the AccessType type. Allow permission The permission that grants access to a permission type. The allow element indicates that a particular user or group is able to execute the defined permission. allow Deny permission The permission that denies access to a permission type. The deny element indicates that a particular user or group is not able to execute the defined permission. deny Permission order The order in which the permission rules should be applied. The order attribute defines which rule should be applied first to obtain the desired access control. The acceptable values are defined in a list of 'allowFirst' and 'denyFirst'. allowFirst Authentication system The authentication system is used to verify the user or group to whom access is allowed or denied. The authentication system determines the set of principals (users + groups) that can be used in the access control list, and the membership of users in groups. This element is intended to provide a reference to the authentication system that is used to verify the user or group. This reference is typically in the form of a URI, which includes the connection protocol, Internet host, and path to the authentication mechanism. ldap://directory.nceas.ucsb.edu:389/o=nceas,c=us Access Rule Access Rules define a user's access to a resource. The AccessRule type defines a list of users that are derived from a particular authentication system (such as an LDAP directory), whether the user or group is allowed or denied access, the extent of their access (write access, or only read access). User or group The user or group (principal) for which the access control applies. The principal element defines the user or group to which the access control rule applies. The users and groups must be defined in the authentication system described in the authSystem element. berkley Type of permission The type of permission being granted or denied for the resource. The permission that is being granted or denied to a particular user or group for a given resource. The list of permissions come from a predetermined list (applicable to an LDAP authentication system): (allow/deny viewing of the resource), 'write' (allow/deny modification of the resource), 'changePermission' (ability to modify access restrictions) and 'all' (allow read/write, and the changePermission). This element also allows other permissions that may be applicable to some other authentication system. read