Enhancing Heart-Beat-Based Security for mHealth Applications.

Area of Science:

• Biometrics
• Cybersecurity
• Mobile Health (mHealth)

Background:

• Heart-beat-based security uses inter-pulse intervals (IPI) for key generation in mHealth.
• Existing research lacks detailed real-world security characterization for IPI-based systems.

Purpose of the Study:

• Evaluate IPI-based security key strength for entity authentication in real systems.
• Investigate factors affecting security: heart-rate variability (HRV), sensor sampling, and inter-sensor variability.
• Introduce and assess a novel method, inter-multi-pulse interval (ImPI), to enhance key entropy.

Main Methods:

• Characterized IPI-based security key strength considering HRV, sensor sampling, and inter-sensor variability.
• Evaluated authentication time (average and worst-case).
• Introduced and analyzed the ImPI method for key generation.

Main Results:

• Maximal key strength for a 60-bit key varied significantly (5.7 to 29.2 bits) based on subject HRV.
• Using multiple, less-entropic keys improved strength by mitigating inter-sensor variability.
• ImPI increased key strength by up to 3.4x (+19.2 bits) for low HRV subjects, with a 4.8x longer generation time.

Conclusions:

• IPI-based security strength is highly dependent on individual HRV and system factors.
• The novel ImPI method offers a promising approach to bolster mHealth security, particularly for users with limited HRV.
• Optimizing key generation time versus security strength is crucial for practical implementation.