Understanding Face Anti-Spoofing Spoofing Challenges Biometric Certification Spoof Detection Techniques Remote Photoplethysmography CNN Approaches Sensor-Aware Loss Function User-Specific Adaptation Strategies On-Device Adaptation Personalized Security Tackling Facial Spoofing Mechanisms Liveness Detection Signal Extraction Biometric Spoof Detection Methods Convolutional Neural Networks LSTM-Based Models Evaluating Anti-Spoofing Effectiveness SiW Database Utilization Experimental Results Mobile Implementation Challenges Dataset Integrity Algorithm...