David Dale

Glassbox Tool Exposes Browser Fingerprinting Risks and Limitations of Incognito Mode

Developer and security researcher David Dale has released Glassbox, an open tool that runs over 30 browser fingerprinting checks to show how identifiable a user appears to trackers. The service evaluates Canvas, WebGL, installed fonts, WebAssembly functions, available APIs, third-party authentication state, and audio processing characteristics entirely in the browser. Results include raw test data and an identifiability score capped at roughly 33 bits, sufficient in theory to single out one person among the global population. Tests reported by The Register showed Chrome at 99 percent identifiability, Firefox at 89 percent, and Tor Browser at 56 percent, though these figures rely on a mathematical model rather than real-world visitor databases. Dale warns that overly hardened configurations can increase uniqueness and recommends using Tor or VPN together with WebRTC leak prevention to blend into larger anonymity sets.