In August 2013, President Obama announced several initiatives to give the public greater confidence in the oversight of the NSA's foreign intelligence programs. The creation of a full-time Civil Liberties and Privacy Officer at NSA was among the reforms cited, and recently they have issued this report PDF ; the following image is taken from it:
To illustrate the process, assume an NSA intelligence analyst identifies or learns that phone number (202) 555-1234 is being used by a suspected international terrorist. This is the “specific selection term” or “selector” that will be submitted to the FISC (or the Attorney General in an emergency) for approval using the RAS standard. Also assume that, through NSA’s examination of metadata produced by the provider(s) or in NSA’s possession as a result of the Agency’s otherwise lawfully permitted signals intelligence activities (e.g., activities conducted pursuant to Section 1.7(c)(1) of Executive Order 12333, as amended), NSA determines that the suspected terrorist has used a 202 area code phone number to call (301) 555-4321. The phone number with the 301 area code is a “first-hop” result. In turn, assume that further analysis or production from the provider(s) reveals (301) 555-4321 was used to call (410) 555-5678. The number with the 410 area code is a “second-hop” result.
Once the one-hop results are retrieved from the NSA’s internal holdings, the list of FISC-approved specific selection terms, along with NSA’s internal one-hop results, are submitted to the provider(s). The provider(s) respond to the request based on the data within their holdings with CDRs that contain FISC-approved specific selection terms or the one-hop selection term. One-hop returns from providers are placed in NSA’s holdings and become part of subsequent query requests, which are executed on a periodic basis. Historical bulk data collected under Section 215 of the USA PATRIOT Act will never be included when querying internal holdings.
Absent information to the contrary, NSA must presume that each user of each of the phone numbers in the above example is a U. S. person, since each phone number has a U.S. area code. NSA’s FISC- approved minimisation procedures for the USA FREEDOM Act prohibit NSA from disseminating any known or presumed U.S. person information that does not constitute foreign intelligence information related to international terrorism or information necessary to understand foreign intelligence information related to international terrorism or assess its importance or is not evidence of a crime. In addition, the minimisation procedures require NSA to destroy promptly any CDRs that are determined not to contain foreign intelligence information. The procedures also set a maximum retention period for CDRs obtained pursuant to the FISC’s orders of no more than 5 years after initial delivery to NSA, except that NSA may retain any CDR (or information derived therefrom) that was the basis of a properly approved dissemination of foreign intelligence information.