public static String calculatePhotoHash( Element vcard )
    {
        if ( vcard.element("PHOTO") == null )
        {
            return "";
        }
        final Element element = vcard.element("PHOTO").element("BINVAL");
        if ( element == null )
        {
            return "";
        }

        final byte[] photo = Base64.getDecoder().decode(element.getTextTrim());
        return StringUtils.hash(photo, "SHA-1");
    }
Controls if MUC occupants can request vCards / avatars.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/spi/IQMUCvCardHandler.java