Although this is safer than sending the password over the network, the client, and other servers, are still at high risk when the server is successfully attacked. This is usually done with the assistance of some third party Certificate Authority, which provides a clearly defined level of support for a guarantee that the server is who it says it is. This means that an eavesdropper can't learn potentially sensitive information about your personal finances, or anything else you manage on-line. When you have many users, you need to group them for two reasons. ACLs may also be used by servlets.
Users often have home directories.
Those users may be assigned to groups . ACLs assign permissions to users and groups, such as the permission to GET a web page or to POST form data to a servlet. ACLs may also deny permissions. Users, groups, and ACLs are all scoped within a realm . Users with the same name, but in different realms, normally have no relationship.