BIOMETRIC RELIANT SYSTEM AND METHOD

1 . A biometric blockchain card for secure communication, comprising:

a card body dimensioned to approximate a standard credit card form factor and comprising a layered core including at least a first thermoplastic layer and a second thermoplastic layer defining through-holes or cutouts for component placement;

a biometric sensor module embedded within the layered core and configured to capture a fresh biometric sample from a user for each authentication session;

a memory configured to store helper data comprising non-sensitive parity bits derived from a fuzzy extractor during enrollment, wherein no static cryptographic private key and no raw biometric data are persistently stored in the memory;

a processor disposed within the layered core and configured to:

(i) extract features from the fresh biometric sample to form a feature vector,

(ii) transform the feature vector through hashing with a user-specific salt stored in tamper-resistant memory to produce a hashed output,

(iii) apply error correction to the hashed output using the stored helper data to regenerate a cryptographic private key that exists only transiently in device memory during the authentication session, and

(iv) authenticate to a private blockchain ledger using the regenerated cryptographic private key; and

a communication interface embedded in the layered core and configured to transmit a join request signed with the regenerated cryptographic private key for validation by a consensus mechanism to register the user, and to derive session keys for encrypted communications recorded as hashes on the private blockchain ledger to verify trust among network participants.

2 . The biometric blockchain card of claim 1 , wherein the biometric sensor module comprises a capacitive fingerprint reader comprising a grid of electrodes on a silicon substrate configured to detect ridge and valley patterns through capacitance changes, the capacitive fingerprint reader embedded in a surface of the card body via a thin protective overlay allowing direct finger contact sensing.

3 . The biometric blockchain card of claim 1 , wherein the processor is further configured to perform match-on-card processing by comparing a template generated from the fresh biometric sample against encrypted templates enrolled during setup, using a similarity metric, and wherein a successful match at or above an adjustable threshold unlocks key generation while a failed match logs the event for auditing.

4 . The biometric blockchain card of claim 1 , wherein the biometric sensor module further supports liveness detection through at least one of: pulse oximetry diodes measuring blood flow via light absorption at multiple wavelengths, or sonic sensors configured to detect epidermis layer uniqueness and blood flow.

5 . The biometric blockchain card of claim 1 , wherein the cryptographic private key comprises an elliptic curve cryptography private key, and wherein the processor further comprises a cryptographic processor with hardware accelerators for hashing functions including secure hash algorithm 256 .

6 . The biometric blockchain card of claim 1 , wherein the layered core further comprises embedded electronics encapsulated by a crosslinkable polymer composition dispensed between the thermoplastic layers and filling the through-holes, the crosslinkable polymer composition cured to form a flexible solid with a Shore D hardness of 10-85 and tensile strength of 20-100 MPa, providing physical protection against moisture, bending, and impact.

7 . The biometric blockchain card of claim 1 , wherein the communication interface comprises at least one of: near field communication via an antenna structure comprising concentric wire coils tuned to 13.56 MHz radio frequency signals for ISO/IEC 14443 compliance, or bluetooth low energy operating at 2.4 GHz with support for bluetooth low energy 5.0 protocols.

8 . The biometric blockchain card of claim 1 , further comprising an antenna structure disposed on or at least partially embedded within a substrate film within the layered core, the antenna structure configured to capture induced voltages from an electromagnetic field to power the biometric sensor module and the processor without requiring an on-board battery.

9 . The biometric blockchain card of claim 1 , wherein during enrollment the biometric sensor module captures multiple biometric samples to build robust templates with error tolerance, the templates encrypted and stored in non-volatile memory on the card and never transmitted off-card.

10 . A biometric authentication device for secure decentralized communication, comprising:

a card body comprising a core layer including a substrate film, an antenna structure disposed on or at least partially embedded within the substrate film and configured to generate energy through induction in an electromagnetic field, a system-in-package comprising at least one chip disposed on or embedded within the substrate film and electrically connected with the antenna structure, and a crosslinked polymer composition disposed on both sides of the substrate film;

a capacitive fingerprint reader integrated into a surface of the card body and configured to capture fingerprint data from a user;

a cryptographic processor electrically connected to the system-in-package and configured to:

receive extracted features from the captured fingerprint data,

combine the extracted features with a user-specific salt via a secure one-way hashing function,

apply error correction using helper data comprising parity bits stored on the device to regenerate a cryptographic private key from the captured fingerprint data without retrieving a stored static key, the cryptographic private key existing only transiently in device memory, and

sign a transaction request using the regenerated cryptographic private key; and

a communication interface configured to transmit the signed transaction request to a private blockchain ledger for authentication and to derive session keys for encrypted communications recorded as hashes on the private blockchain ledger for trust verification among network participants.

11 . The biometric authentication device of claim 10 , wherein the antenna structure comprises concentric wire coils of copper or copper alloy having 2-8 turns of 50 to 300-micron copper wire tuned to 13.56 MHz radio frequency signals.

12 . The biometric authentication device of claim 10 , wherein the system-in-package comprises at least two chips for different functions, including a microcontroller unit and the cryptographic processor.

13 . The biometric authentication device of claim 10 , further comprising a microcontroller unit configured to coordinate biometric data processing by interfacing with the capacitive fingerprint reader via at least one of a serial peripheral interface, an inter-integrated circuit port, or a universal asynchronous receiver-transmitter, the microcontroller unit configured to enter a sleep mode drawing less than 1 μA and activated by sensor interrupts.

14 . The biometric authentication device of claim 10 , wherein the core layer includes no battery and the device is powered exclusively by energy harvested through induction in the electromagnetic field via the antenna structure.

15 . The biometric authentication device of claim 10 , wherein the card body further comprises cutouts configured to receive embedded elements with a gap of at least 150 microns between components and a cutout edge for electromagnetic isolation, and discontinuities extending from an outer edge to the cutouts forming channels with curved and straight portions that create flexible fingers arranged in parallel to distribute pressure and prevent cracking.

16 . A method for secure communication using a biometric blockchain card having a layered core embedding a biometric sensor module, a processor, and a communication interface, the method comprising:

capturing a fresh biometric sample from a user using the biometric sensor module for each authentication session;

extracting features from the fresh biometric sample to produce a feature vector;

transforming the feature vector through hashing with a user-specific salt generated during enrollment and stored in tamper-resistant memory on the card;

applying error correction to the transformed feature vector using helper data comprising non-sensitive parity bits stored on the card to regenerate a cryptographic private key, the cryptographic private key derived from the fresh biometric sample and existing only transiently in device memory during the authentication session such that no static private key is persistently stored on the card;

authenticating to a private blockchain ledger by signing a challenge using the regenerated cryptographic private key;

transmitting a join request via the communication interface, the join request validated by a consensus mechanism to register the user on the private blockchain ledger; and

deriving session keys for encrypted communications, the encrypted communications recorded as hashes on the private blockchain ledger to verify trust among network participants.

17 . The method of claim 16 , further comprising, prior to the capturing step, performing enrollment by:

activating an enrollment mode via a user interface on the card,

capturing multiple biometric samples from the user,

building robust templates with error tolerance from the multiple biometric samples,

encrypting and storing the templates in non-volatile memory on the card such that the encrypted templates are never transmitted off-card, and

generating the user-specific salt and the helper data for use in subsequent authentication sessions.

18 . The method of claim 16 , wherein applying error correction comprises using fuzzy extractors based on at least one of Reed-Solomon codes or Bose-Chaudhuri-Hocquenghem codes to correct errors within a Hamming distance tolerance, ensuring key reproducibility across biometric scans while binding the key to the biometrics irreversibly.

19 . The method of claim 16 , further comprising discarding the regenerated cryptographic private key from device memory after completing the authentication session such that the cryptographic private key is not available for extraction through physical tampering or side-channel attacks.

20 . The method of claim 16 , wherein deriving session keys comprises performing a Diffie-Hellman key exchange bound to the regenerated cryptographic private key to produce symmetric keys for encrypted communications with other users authenticated on the private blockchain ledger.