woocommerce GDPR - save the acceptance of the privacy policy in the database

I use this code to create a second checkbox at the woocommerce checkout (for the privacy policy). To be compatible with the GDPR I would need to be able to prove that the user selected the checkbox. How could I do?

// Add terms and policy check box in checkout page
add_action( 'woocommerce_checkout_after_terms_and_conditions', 'add_terms_and_policy', 20 );
function add_terms_and_policy() {
    $domain = 'woocommerce';

    $gdpr_private_policy_link = sprintf( '<a href="%s" target="_blank">%s</a>',
        home_url("/protest/privacy-policy/"), // The button link to the GDPR privacy policy page
        __( "Privacy Policy", $domain )       // The button text
    );

    woocommerce_form_field( 'gdpr_terms', array(
        'type'          => 'checkbox',
        'class'         => array( 'terms gdpr_terms' ),
        'input_class'   => array('woocommerce-form__input-checkbox'),
        'label_class'   => array('woocommerce-form__label-for-checkbox'),
        'label'         => '<span>' . sprintf(
            __( "I have read and accept the %s and understand how you manage my Data under GDPR", $domain ),
            $gdpr_private_policy_link
        ) . '</span>',
        'required'      => true,
    ), '');
}

// Validate required GDPR private policy checkbox
add_action( 'woocommerce_after_checkout_validation', 'terms_and_policy_validation', 20, 2 );
function terms_and_policy_validation( $data, $errors ) {
    if ( ! isset( $_POST['gdpr_terms'] ) ){
        $domain = 'woocommerce';

        $gdpr_text = sprintf(
            __( "I have read and accept the %s and understand how you manage my Data under GDPR", $domain ),
            __( "Privacy Policy", $domain )
        );

        $errors->add( 'gdpr_terms', sprintf( __( 'You must accept "%s".', $domain ), $gdpr_text ), 'error' );
    }
}