Browse Definitions :
Definition

entity tag (ETag)

Contributor(s): Matthew Haughn

An entity tag (ETag) is an HTTP header used for Web cache validation and conditional requests from browsers for resources.

Etags use persistent identification elements (PIE) that have been tagged to the user’s browser. Although a user may remove HTTP cookies, ETags store the same information along with covert backup to reconstitute the data of deleted cookies.

 Most typically, ETags request Web resources on the condition that they have been updated since the user’s last visit to the site. For instance:

A user may visit a site featuring a background that changes every week. On the first visit in a new week, the browser checks the cache and, finding no image or an outdated one, downloads the current background and caches it. If the user had already visited the site that week, the browser would receive the return response that the image had not changed. In that case, the browser would use the local copy in the cache, saving bandwidth and speeding load time.

HTML5 local storage and cache cookies enabled through ETags are also one method used to respawn cookies. Respawning cookies are used by consumer tracking firms to address the issue of user deletion or denial of cookies. The practice can also be used to track users for other purposes, such as keeping tabs on hackers.

This was last updated in October 2014

Continue Reading About entity tag (ETag)

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • PCI DSS (Payment Card Industry Data Security Standard)

    The Payment Card Industry Data Security Standard (PCI DSS) is a widely accepted set of policies and procedures intended to ...

  • risk management

    Risk management is the process of identifying, assessing and controlling threats to an organization's capital and earnings.

  • compliance framework

    A compliance framework is a structured set of guidelines that details an organization's processes for maintaining accordance with...

SearchSecurity

  • Trojan horse (computing)

    In computing, a Trojan horse is a program downloaded and installed on a computer that appears harmless, but is, in fact, ...

  • identity theft

    Identity theft, also known as identity fraud, is a crime in which an imposter obtains key pieces of personally identifiable ...

  • DNS over HTTPS (DoH)

    DNS over HTTPS (DoH) is a relatively new protocol that encrypts domain name system traffic by passing DNS queries through a ...

SearchHealthIT

  • telemedicine (telehealth)

    Telemedicine is the remote delivery of healthcare services, such as health assessments or consultations, over the ...

  • Project Nightingale

    Project Nightingale is a controversial partnership between Google and Ascension, the second largest health system in the United ...

  • medical practice management (MPM) software

    Medical practice management (MPM) software is a collection of computerized services used by healthcare professionals and ...

SearchDisasterRecovery

SearchStorage

  • M.2 SSD

    An M.2 SSD is a solid-state drive (SSD) that conforms to a computer industry specification and is used in internally mounted ...

  • kilobyte (KB or Kbyte)

    A kilobyte (KB or Kbyte) is a unit of measurement for computer memory or data storage used by mathematics and computer science ...

  • virtual memory

    Virtual memory is a memory management capability of an operating system (OS) that uses hardware and software to allow a computer ...

Close