Screen

1. What is Screen Fingerprinting

The browser’s Screen Fingerprint refers to a set of device-specific display properties exposed through the window.screen object:

screen.width
screen.height
screen.colorDepth
screen.pixelDepth
screen.availWidth
screen.availHeight
window.devicePixelRatio

These values help platforms infer:

• Device type (desktop, mobile, tablet)
• Likely zoom or scaling settings
• The number of monitors (via window.screenLeft, window.screenTop)
• User regions (via resolution + OS, sometimes cross-checked with IP)
• Browser maximization state (heuristically via screen vs window dimensions)

Although screen fingerprinting alone is not enough to uniquely identify a user, when combined with other signals like Canvas, User Agent, Timezone, and WebGL, it becomes a core element of browser fingerprint uniqueness.

2. How Platforms Detect Screen Fingerprints

Anti-multiaccounting and fingerprinting platforms monitor screen-related values extensively. Detection techniques include:

1. Resolution Consistency Check – Users with different screen.width and screen.height values than typical devices for their OS or geography may raise suspicion.
2. devicePixelRatio Analysis – Some platforms analyze screen density (window.devicePixelRatio) to determine if it aligns with real-world browser behavior (e.g., Retina displays on macOS).
3. Available Screen Size vs Window Size Monitoring – A commonly used heuristic: compare screen dimensions to actual window size to detect whether the browser is fullscreen, maximized, on a VM, or distorted.
4. Cross-checking with Device Type – For example, if the screen shows a resolution typical of a desktop computer but the user agent claims Android, this mismatch may be used to flag sessions.
5. Unrealistic Value Detection – Some anti-spoofing engines can detect if spoofed resolutions are non-existent “outliers” for the target user agent profile, indicating fingerprint manipulation tools.
6. DOMRect and Layout Behavior Injection Tracking – Platforms may monitor how screen-based layout elements (window.screenX, window.scrollX) behave during resizing to detect synthetic environments.

Screen values are often linked with behavioral spoofing detection logic, and are used by rule-based or ML-driven systems to compute a device trust score during user onboarding or authentication.

3. How FlashID Modifies Screen Fingerprints

FlashID gives users the ability to fully customize and persist the screen fingerprint data, ensuring that each browser profile acts like a distinct physical device, even when launched from the same system.

Key screen manipulation features include:

1. Resolution Masking

• Set screen.width and screen.height per-browser to mimic real-world devices
• Choose from standard sizes or input custom ones (e.g., 1440x900, 1920x1080, 1242x2208)

2. Color Depth & Pixel Depth Emulation

• Spoof screen.colorDepth, screen.pixelDepth to reflect the simulated hardware accurately (e.g., 24-bit, 8-bit, 32-bit)

3. Device Pixel Ratio Control

• Customize window.devicePixelRatio per instance (e.g., 2.0 for Retina MacBooks or 1.0 for old Windows laptops)

4. A realistic availWidth/availHeight Simulation

• Reflect the available desktop area (excluding taskbars or docks), increasing realism for desktop patterns

5. Screen Orientation Feature Control

• Simulate screen orientation (portrait or landscape) based on expected device type

6. Resolution-to-User-Agent Matchmaking

• FlashID auto-recommends resolution and device size profiles based on selected user agent and operating system — helping avoid mismatch flags

7. ScreenChangeEvent Behavior Mimicking

• Fake orientationchange or resize events to mimic real browsing or device-sensor behavior

By fully controlling the window.screen API, FlashID eliminates cross-session leakage that could tie multiple profiles together due to shared screen signatures, empowering users to implement plausible and undetectable multi-account operations.

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