XBL – eXploits BlockList What is the eXploits Blocklist (XBL)? The Exploits Block List (XBL) by “Spamhaus Project” is a real-time database of IP addresses
XMPP (eXtensible Messaging and Presence Protocol) – is an open XML-based protocol originally aimed at near-real-time, extensible instant messaging (IM) and presence information (RFC3920). XMPP
Expected Result (XRES): The value pre-calculated by the network, which the mobile device’s response (RES) is compared against. Analogy: The correct answer on an answer