GUID

 

By Vangie Beal

A Globally Unique Identifier (GUID) is a unique ID that is computed by Windows and Windows applications. It’s a 128-bit number used to identify user accounts, documents, software, hardware, database entries, sessions, and other items. For example, a website may generate a GUID and assign it to a user’s browser to record and track the session.

GUID may also be referred to as a Universally Unique Identifier (UUID). The two terms are synonymous. GUIDs can be used for:

  • Setting a unique primary key in databases
  • Setting a unique filename for uploaded files
  • Setting a unique name for resources
  • Creating and registering unique IDs without contacting a central authority

A GUID follows a specific structure defined in RFC 4122 and comes in multiple formats. However, all variants follows the same structure:

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

M represents the version. N represents the variant.

Types of GUIDs

The general types of GUIDs include:

  • Random: Uses a system to generate a random, 128-bit number
  • Time-based: Creates a GUID based on the current time
  • Hardware-based: Makes a GUID with certain portions based on hardware features, such as the MAC address of a network card.
  • Content-based (MD5 or SHA-1 hash of data): Creates a GUID based on a hash of the file contents. Files with the same contents will be assigned the same GUID.

Creating a GUID

To create a GUID, there are a multitude of online GUID generators, such as guidgenerator.com. In addition, there are also GUID libraries for programming languages such as PHP, Ruby, and Python.

 

 

Vangie Beal
Vangie Beal
Vangie Beal is a freelance business and technology writer covering Internet technologies and online business since the late '90s.

Top Articles

List of Windows Operating System Versions & History [In Order]

The Windows operating system (Windows OS) refers to a family of operating systems developed by Microsoft Corporation. We look at the history of Windows...

How to Create a Website Shortcut on Your Desktop

Website Shortcut on Your Desktop reviewed by Web Webster   This Webopedia guide will show you how to create a website shortcut on your desktop using...

What are the Five Generations of Computers? (1st to 5th)

Reviewed by Web Webster Each generation of computer has brought significant advances in speed and power to computing tasks. Learn about each of the...

Hotmail [Outlook] Email Accounts

Launched in 1996, Hotmail was one of the first public webmail services that could be accessed from any web browser. At its peak in...

HighLevel CRM

HighLevel is a sales and marketing customer relationship management (CRM) solution designed by...

Unified Endpoint Management (UEM)

As enterprise networks become increasingly distributed with growing numbers of remote workers, unified...

Decision Intelligence

Decision intelligence combines business intelligence (BI) and artificial intelligence (AI) models to improve...