page_title: HTTP cookie
section_title: Background
hierarchical_section_title: HTTP cookie / Background
caption_attribution_description: English: Stack of choc-chip cookies
context_page_description: An HTTP cookie is a small piece of data stored on the user's computer by the web browser while browsing a website. Cookies were designed to be a reliable mechanism for websites to remember stateful information or to record the user's browsing activity. They can also be used to remember pieces of information that the user previously entered into form fields, such as names, addresses, passwords, and payment card numbers.
  Cookies perform essential functions in the modern web. Perhaps most importantly, authentication cookies are the most common method used by web servers to know whether the user is logged in or not, and which account they are logged in with. Without such a mechanism, the site would not know whether to send a page containing sensitive information, or require the user to authenticate themselves by logging in. The security of an authentication cookie generally depends on the security of the issuing website and the user's web browser, and on whether the cookie data is encrypted. Security vulnerabilities may allow a cookie's data to be read by a hacker, used to gain access to user data, or used to gain access to the website to which the cookie belongs.
caption: HTTP cookies share their name with a popular baked treat.
exif: {"Image ImageWidth": "6000", "Image ImageLength": "4000", "Image BitsPerSample": "[8, 8, 8]", "Image PhotometricInterpretation": "2", "Image Make": "NIKON CORPORATION", "Image Model": "NIKON D5500", "Image Orientation": "Horizontal (normal)", "Image SamplesPerPixel": "3", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS6 (Windows)", "Image DateTime": "2016:11:11 18:02:50", "Image ExifOffset": "284", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1070", "Thumbnail JPEGInterchangeFormatLength": "5019", "EXIF ExposureTime": "1/125", "EXIF FNumber": "7/2", "EXIF ExposureProgram": "Manual", "EXIF ISOSpeedRatings": "250", "EXIF SensitivityType": "Recommended Exposure Index", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2016:11:11 14:59:07", "EXIF DateTimeDigitized": "2016:11:11 14:59:07", "EXIF ShutterSpeedValue": "870723/125000", "EXIF ApertureValue": "361471/100000", "EXIF ExposureBiasValue": "-5", "EXIF MaxApertureValue": "8/5", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash fired, compulsory flash mode, return light not detected", "EXIF FocalLength": "35", "EXIF SubSecTimeOriginal": "54", "EXIF SubSecTimeDigitized": "54", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "6000", "EXIF ExifImageLength": "4000", "EXIF FocalPlaneXResolution": "83841555/32768", "EXIF FocalPlaneYResolution": "83841555/32768", "EXIF FocalPlaneResolutionUnit": "3", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CVAPattern": "[2, 0, 2, 0, 0, 1, 1, 2]", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Manual Exposure", "EXIF WhiteBalance": "Manual", "EXIF DigitalZoomRatio": "1", "EXIF FocalLengthIn35mmFilm": "52", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0", "EXIF BodySerialNumber": "4390819", "EXIF LensSpecification": "[35, 35, 9/5, 9/5]", "EXIF LensModel": "35.0 mm f/1.8"}