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Local shared objects (LSOs), commonly called Flash cookies (due to their similarities with HTTP cookies), are pieces of data that websites which use Adobe Flash may store on a user's computer. Local shared objects have been used by all versions of Flash Player (developed by Macromedia, which was later acquired by Adobe Systems) since version 6. Flash cookies, which can be stored or retrieved whenever a user accesses a page containing a Flash application, are a form of local storage. Similar to that of cookies, they can be used to store user preferences, save data from Flash games, or to track users' Internet activity.〔(The Guardian newspaper, When the cookies crumbled, so did your web anonymity, 5 October 2014 )〕 LSOs have been criticised as a breach of browser security, but there are browser settings and addons to limit the duration of their storage. == Storage == Local shared objects contain data stored by individual websites. Data is stored in the Action Message Format. With the default settings, the Flash Player does not seek the user's permission to store local shared objects on the hard disk. By default, a SWF application running in Flash Player from version 9 to 11 (as of Sept 1, 2011) may store up to of data to the user's hard drive. If the application attempts to store more, a dialog asks the user whether to allow or deny the request. Adobe Flash Player does not allow third-party local shared objects to be shared across domains. For example, a local shared object from "www.example.com" cannot be read by the domain "www.example.net".〔 However, the first party website can always pass data to a third party via some settings found in the dedicated XML file and passing the data in the request to the third party. Also, third party LSOs are allowed to store data by default. By default LSO data is shared across browsers on the same machine. As an example: * A visitor accesses a site using their Firefox browser, then views a page displaying a specific product, then closes the Firefox browser, the information about that product can be stored in the LSO. * If that same visitor, using the same machine now opens an Internet Explorer browser and visits any page from the site viewed in Firefox, the site can read the LSO value(s) in the Internet Explorer browser, and display dynamic content or otherwise target the visitor. This is distinct from cookies which have directory isolated storage paths for saved cookies while LSOs use a common directory path for all browsers on a single machine. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Local shared object」の詳細全文を読む スポンサード リンク
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