This SIDToday post dated 18 January 2006 discusses how NSA is dealing with a new obstacle: IP telephony services whereby a target can obtain a US or UK phone number. A VoIP Normalization Working Group worked with NSA’s Office of General Counsel to develop a system whereby such numbers can be classified as of non US status, where certain legal protections would not apply: see the Intercept article 328 NSA Documents Reveal “Vast Network” of Iranian Agents, Details of a Key Intelligence Coup, and a Fervor for Voice-Matching Technology, 15 August 2015.
This NSA presentation from 24 June 2009 explains how to use the email search functionality within XKeyScore: see the Intercept article XKEYSCORE: NSA’s Google for the World’s Private Communications, 1 July 2015.
These six slides from 2010 GCHQ presentation outline the results of a trial operation to acquire SIM encryption keys: see the Intercept article The Great SIM Heist: How Spies Stole the Keys to the Encryption Castle, 19 February 2015.
This CSE (then CSEC) presentation from 2012 describes the Canadian agency’s file download monitoring operation: see the Intercept article Canada Casts Global Surveillance Dragnet Over File Downloads, 28 January 2015.