Windows Security Identifier

Windows grants or denies access and privileges to resources based on access control lists (ACLs), which use these SIDs to uniquely identify users and their group memberships. When a user logs into a computer, an access token is generated that contains user and group SIDs and user privilege levels. When a user requests access to a resource, the access token is checked against the ACL to permit or deny particular action on a particular object. SIDs are useful for troubleshooting issues with security audits, Windows server, and domain migrations. SID has the format as follows: S-1-5-21-7623811015-3361044348-030300820-1013 S – The string is a SID.1 – The revision level (the version of the SID specification).5 – The identifier authority value.21-7623811015-3361044348-030300820 – domain or local computer identifier1013 – a Relative ID (RID). Any group or user that is not created by default will have a Relative ID of 1000 or greater. Possible identifier authority values are: 0 – Null Authority1 – World Authority2 – Local Authority3 – Creator Authority4 – Non-unique Authority5 – NT Authority9 – Resource Manager Authority Windows SID Resolver from wingeek.com is a free utility that allows you to resolve a Windows SID.

Simply enter the SID you want to resolve, and the utility will identify what account the SID is from. Additional information is available on KB243330.