public Integer getDigits() throws GuacamoleException {

        // Do not reveal code size unless enrollment is in progress
        if (key == null)
            return null;

        return confService.getDigits();
        
    }
Returns the number of digits used for each TOTP code. If the user's key
is not being exposed to facilitate enrollment, this value will not be
exposed either.

@return
    The number of digits used for each TOTP code, or null if the user's
    key is not being exposed to facilitate enrollment.

@throws GuacamoleException
    If the number of digits cannot be read from guacamole.properties.
extensions/guacamole-auth-totp/src/main/java/org/apache/guacamole/auth/totp/form/AuthenticationCodeField.java