security identifier (SID)

The security ID (SID) is used to uniquely identify a user in a security system. Security IDs can be assigned to individual persons or entire user groups.

Due to the large number of user names, it is possible that many ambiguities occur in the network, causing corresponding problems. For this reason, the Security Identifier (SID) is used to assign each user a unique identifier that no other user has. With the SID identifier, which is supported by the operating systems, the user is usually also assigned rights and can be identified in the entire network under this SID identifier. If the user name is deleted from the network, its security identifier also expires.

Under Windows, the security identifier consists of the revision number of the operating system, the identifier authority, the domain ID and the user ID.