Browse Definitions:

unique device identifier (UDID)

Contributor(s): Stan Gibilisco

A unique device identifier (UDID) is a 40-character string assigned to certain Apple devices including the iPhone, iPad, and iPod Touch. Each UDID character is a numeral or a letter of the alphabet.

Using the UDID, third parties, particularly app vendors, can track subscriber behavior. These companies can learn what the user likes, and then tailor advertising accordingly. Unfortunately, this UDID feature carries the potential for abuse. In 2010, some users began to complain about unauthorized exposure of their individual identities. Some apps, for example, associated users' real names with device UDIDs without subscribers' knowledge or permission. 

Because of mounting privacy concerns on the part of device owners, Apple began discouraging app developers from tracking customers with UDIDs. In 2012, Apple began rejecting apps that make use of UDIDs.

This was last updated in June 2012

Continue Reading About unique device identifier (UDID)

Join the conversation

1 comment

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

Look at online service
You can find UDID, IMEI and Serial Number just in few taps


File Extensions and File Formats


  • risk map (risk heat map)

    A risk map, also known as a risk heat map, is a data visualization tool for communicating specific risks an organization faces. A...

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...


  • cloud ecosystem

    A cloud ecosystem is a complex system of interdependent components that all work together to enable cloud services.

  • cloud services

    Cloud services is an umbrella term that may refer to a variety of resources provided over the internet, or to professional ...

  • uncloud (de-cloud)

    The term uncloud describes the action or process of removing applications and data from a cloud computing platform.


  • federated identity management (FIM)

    Federated identity management (FIM) is an arrangement that can be made among multiple enterprises to let subscribers use the same...

  • cross-site scripting (XSS)

    Cross-site scripting (XSS) is a type of injection security attack in which an attacker injects data, such as a malicious script, ...

  • firewall

    In computing, a firewall is software or firmware that enforces a set of rules about what data packets will be allowed to enter or...




  • bad block

    A bad block is an area of storage media that is no longer reliable for storing and retrieving data because it has been physically...

  • all-flash array (AFA)

    An all-flash array (AFA), also known as a solid-state storage disk system, is an external storage array that uses only flash ...

  • volume manager

    A volume manager is software within an operating system (OS) that controls capacity allocation for storage arrays.


  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.