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chromium / chromium / src / main / . / content / browser / btm
tree: 81c045c78a85f70a27ab0cd1038c1ed7581c1fb5 [path history] [tgz]
  1. btm_bounce_detector.cc
  2. btm_bounce_detector.h
  3. btm_bounce_detector_browsertest.cc
  4. btm_bounce_detector_unittest.cc
  5. btm_browsertest_utils.cc
  6. btm_browsertest_utils.h
  7. btm_database.cc
  8. btm_database.h
  9. btm_database_migrator.cc
  10. btm_database_migrator.h
  11. btm_database_migrator_unittest.cc
  12. btm_database_unittest.cc
  13. btm_helper_browsertest.cc
  14. btm_navigation_flow_detector.cc
  15. btm_navigation_flow_detector.h
  16. btm_navigation_flow_detector_browsertest.cc
  17. btm_page_visit_observer.cc
  18. btm_page_visit_observer.h
  19. btm_page_visit_observer_browsertest.cc
  20. btm_page_visit_observer_test_utils.cc
  21. btm_page_visit_observer_test_utils.h
  22. btm_page_visit_observer_unittest.cc
  23. btm_service_impl.cc
  24. btm_service_impl.h
  25. btm_service_unittest.cc
  26. btm_short_visit_observer.cc
  27. btm_short_visit_observer.h
  28. btm_short_visit_observer_browsertest.cc
  29. btm_state.cc
  30. btm_state.h
  31. btm_storage.cc
  32. btm_storage.h
  33. btm_storage_unittest.cc
  34. btm_test_utils.cc
  35. btm_test_utils.h
  36. btm_test_utils_browsertest.cc
  37. btm_utils.cc
  38. btm_utils.h
  39. btm_utils_unittest.cc
  40. cookie_access_filter.cc
  41. cookie_access_filter.h
  42. cookie_access_filter_unittest.cc
  43. DEPS
  44. DIR_METADATA
  45. OWNERS
  46. persistent_repeating_timer.cc
  47. persistent_repeating_timer.h
  48. persistent_repeating_timer_unittest.cc
  49. README.md
content/browser/btm/README.md

Bounce Tracking Mitigations (BTM)

This directory contains the code for Chromium's Bounce Tracking Mitigation (BTM) feature. BTM aims to mitigate the privacy impact of “bounce tracking,” a technique used to track users across websites without relying on third-party cookies.

What is bounce tracking?

Bounce tracking involves redirecting users through a tracker website, often without their knowledge or interaction. This allows the tracker to set or access first-party cookies, effectively circumventing third-party cookie restrictions and user privacy preferences.

How does BTM work?

BTM detects potential bounce tracking by analyzing website behavior, including:

  • Short dwell times on a website before redirecting.
  • Programmatic redirects (as opposed to user-initiated ones).
  • Writing to storage (cookies, etc.) before redirecting.

If BTM determines that a website is likely involved in bounce tracking and there‘s no indication of legitimate user interaction with the site, it automatically deletes the site’s storage (eTLD+1) after a brief grace period.

Goals of BTM

  • Reduce cross-site tracking: Limit the ability of bounce trackers to identify and track users across different contexts.
  • Protect user privacy: Prevent bounce tracking from circumventing third-party cookie restrictions.
  • Maintain compatibility: Avoid disrupting legitimate use cases like federated logins and payment flows that rely on redirects.
  • Adaptability: Mitigate tracking by short-lived domains that may evade traditional blocklist-based approaches.

Non-Goals

  • Replacing third-party cookie blocking: BTM is primarily designed for environments where third-party cookies are already restricted.
  • Mitigating tracking by sites with significant first-party activity: BTM focuses on incidental parties (sites without meaningful user interaction) and may not be effective against sites with substantial first-party engagement.

Further Reading