Hand-based biometric authentication

A physical card, comprising:

• a card body;
• a plurality of sensors around an outer edge of the card body;
• one or more memories, in the card body, that store a touch validation model;
• and
• one or more processors, in the card body and communicatively coupled to the plurality of sensors and the one or more memories, configured to cause the physical card to:
• capture, from the plurality of sensors, sensor data indicating a touch profile detected along the outer edge;
• input the touch profile to the touch validation model that determines whether the touch profile sufficiently matches a valid touch profile of one or more valid touch profiles each indicating valid finger placements on the physical card that are based on hand characteristics of a hand including at least one of hand shape, hand size, finger size, or finger length;
• and
• transmit an indication of whether the physical card is enabled, in accordance with an output of the touch validation model.

A method of biometric authentication, comprising:

• capturing, by a physical card using a plurality of sensors positioned around an outer edge of the physical card, sensor data indicating a touch profile along the outer edge,
• wherein the touch profile is indicative of a finger placement of a hand holding the physical card;
• comparing, by the physical card, the touch profile to one or more valid touch profiles each indicating valid finger placements on the physical card that are based on hand characteristics of the hand including at least one of hand shape, hand size, finger size, or finger length;
• determining, by the physical card, that the touch profile sufficiently matches a valid touch profile, of the one or more valid touch profiles, based on comparing the touch profile to the one or more valid touch profiles;
• and
• transmitting, by the physical card to a terminal or a user device, an indication that the physical card is enabled, based on determining that the touch profile sufficiently matches the valid touch profile.