Display Security Identifier

Windows grants or denies access and privileges to resources based on access control lists (ACLs), which use 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 level.

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.

But suppose you need to discover what SID belongs to which user account?

Well you can using a FREE utility called SID Resolver. 

Let's look at in action:

Step One: Open up the Registry (regedit) and look in the registry under the key   HKEY_USERS\

Step Two:  Pick an account like in the example above I created on a test machine in my office.

S-1-5-21-1630341508-1711315318-226566079-1002

Step Three: Click here to download SIDResolver.zip (176 KB)

SID Resolver is compatible with any version of Windows that supports the .Net Framework 3.5

Step Four: Unzip the file and then double click the utility .exe file to run the program.

Step Five: In the windows that appears copy and paste the SID

Step Six: Click the Resolve button and you will see the associated account.

In the example above you will see that this SID is for a user account called Work 2008 on a PC called office-vista.

Standard Accounts on Windows:

S-1-5-18 Local System, a service account that is used by the operating system.
S-1-5-19 Local Service
S-1-5-20 Network Service