Browser Telemetry

Client-Side Sensor

2025

by LockedX Labs

Spoof-Resistant Fingerprinting Architecture

Conventional fingerprinting approaches suffer from a fundamental vulnerability: they rely on easily observable or reproducible browser characteristics that sophisticated automation tools can trivially spoof. User agents can be modified, screen resolutions can be randomized, and plugin lists can be manipulated with minimal effort. Building detection systems around such easily mutable characteristics creates an arms race where attackers need only identify the specific attributes being measured to defeat the entire system.



lx-arc implements multi-layered fingerprinting that focuses on characteristics that are computationally expensive to spoof rather than simply difficult to observe. Our approach combines hardware-level performance signatures, rendering pipeline characteristics, and computational timing patterns that would require comprehensive browser engine modification to successfully replicate.

The system measures how browsers perform complex computational tasks rather than what capabilities they report having. Canvas rendering performance under specific mathematical operations, WebGL shader compilation timing, audio processing latency patterns, and memory allocation behaviors provide fingerprints that are intrinsically tied to the underlying hardware and software stack. Spoofing these characteristics requires not just changing reported values, but actually modifying the fundamental performance characteristics of the browser engine itself.

Cross-validation occurs across multiple measurement modalities simultaneously. Consistency checks ensure that performance signatures align across different browser subsystems in ways that are mathematically predictable for genuine browser environments but extremely difficult to coordinate in spoofed configurations. This multi-modal approach means that successful spoofing requires defeating not just individual tests, but maintaining consistent false signals across dozens of interconnected measurements.

Advanced Proof-of-Work Analysis

The proof-of-work challenge system in lx-arc extends far beyond simple computational puzzles to create sophisticated performance fingerprints that reveal the execution environment characteristics. Our multi-scale timing analysis measures not just whether a client can solve cryptographic challenges, but how those solutions are computed, providing deep insights into whether the computation occurs in a genuine browser environment or an automated system.



Statistical profiling during proof-of-work execution captures timing distribution patterns that differ significantly between human-operated browsers and automated systems. Genuine browsers exhibit natural variation in performance due to multitasking, garbage collection, and system resource contention. Automated systems typically demonstrate unnaturally consistent timing patterns that reflect their optimized, single-purpose execution environments.

Memory behavior tracking during computation provides additional signals that are difficult for automation tools to replicate convincingly. Browser memory allocation patterns, garbage collection timing, and memory pressure responses create signatures that reflect the complex interaction between browser engines, operating systems, and hardware configurations. These patterns are computationally expensive to simulate and nearly impossible to spoof without comprehensive browser engine modification.

Batch analysis techniques examine performance consistency across multiple computational attempts, identifying statistical signatures that distinguish between natural human interaction patterns and the optimized execution characteristics of automated systems. The analysis adapts to different hardware performance levels while maintaining sensitivity to the computational signatures that indicate automation.

Fuzzy Device Clustering

Traditional device fingerprinting attempts to create unique identifiers for individual devices, leading to privacy concerns and brittleness when device configurations change. lx-arc implements fuzzy fingerprinting that focuses on device similarity clustering rather than unique identification. This approach provides the threat intelligence benefits of device tracking while avoiding the privacy implications of persistent unique identifiers.

Our fuzzy fingerprinting algorithm generates 64-character device signatures that group similar devices into stable clusters while remaining resilient to minor configuration changes. Browser updates, driver modifications, and system patches that would break traditional fingerprinting approaches only minimally impact fuzzy cluster assignment. This stability enables long-term threat intelligence while adapting to the natural evolution of device configurations.

Device DNA generation incorporates hardware capabilities, software configuration signatures, and performance characteristics into deterministic cluster assignments that remain consistent across reasonable device variations. The system can identify when two interactions likely originate from similar device configurations without requiring exact matches or storing personally identifying information about specific devices.

Hamming distance calculations enable rapid similarity assessment between device signatures, allowing real-time clustering decisions and efficient threat intelligence correlation. When suspicious patterns are detected from one device in a cluster, the system can apply appropriate scrutiny to similar devices without requiring extensive database lookups or complex pattern matching algorithms.


lx-arc represents advanced research into privacy-preserving behavioral detection that maintains effectiveness against sophisticated automation while respecting user privacy and regulatory compliance requirements. Our approach demonstrates that the most effective bot detection signals are inherently privacy-safe when properly understood and implemented.