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physics

PRISM

PRISM is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand PRISM rather than just read about it. In short: PRISM is a code name for a program under which the United States National Security Agency (NSA) collects internet communications from various U.S. internet companies. The program is also known by the SIGAD US-984XN.

PRISM — main illustration
PRISM — illustration

Key takeaways

  • PRISM belongs to physics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect PRISM to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of PRISM from memory before moving on to harder problems.

Reference excerpt

PRISM is a code name for a program under which the United States National Security Agency (NSA) collects internet communications from various U.S. internet companies. The program is also known by the SIGAD US-984XN. PRISM collects stored internet communications based on demands made to internet companies such as Google and Apple under Section 702 of the FISA Amendments Act of 2008 to turn over any data that match court-approved search terms. Among other things, the NSA can use these PRISM requests to target communications that were encrypted when they traveled across the internet backbone, to focus on stored data that telecommunication filtering systems discarded earlier, and to get data that is easier to handle. PRISM began in 2007 in the wake of the passage of the Protect America Act under the Bush Administration. The program is operated under the supervision of the U.S. Foreign Intelligence Surveillance Court (FISA Court, or FISC) pursuant to the Foreign Intelligence Surveillance Act (FISA). Its existence was leaked six years later by NSA contractor Edward Snowden, who warned that the extent of mass data collection was far greater than the public knew and included what he characterized as "dangerous" and "criminal" activities. The disclosures were published by The Guardian and The Washington Post on June 6, 2013. Subsequent documents have demonstrated a financial arrangement between the NSA's Special Source Operations (SSO) division and PRISM partners in the millions of dollars. Documents indicate that PRISM is "the number one source of raw intelligence used for NSA analytic reports", and it accounts for 91% of the NSA's internet traffic acquired under FISA section 702 authority." The leaked information came after the revelation that the FISA Court had been ordering a subsidiary of telecommunications company Verizon Communications to turn over to the NSA the logs tracking all of its customers' telephone calls. U.S. government officials have disputed criticisms of PRISM in the Guardian and Washington Post articles and have defended the program, asserting that it cannot be used on domestic targets without a warrant. They additionally claim that the program has helped to prevent acts of terrorism, and that it receives independent oversight from the federal government's executive, judicial and legislative branches. On June 19, 2013, U.S. president Barack Obama, during a visit to Germany, stated that the NSA's data gathering practices constitute "a circumscribed, narrow system directed at us being able to protect our people".

Media disclosure of PRISM

Edward Snowden publicly revealed the existence of PRISM through a series of classified documents leaked to journalists of The Washington Post and The Guardian while he was an NSA contractor at the time, thus fleeing to Hong Kong. The leaked documents included 41 PowerPoint slides, four of which were published in news articles. The documents identified several technology companies as participants in the PRISM program, including Microsoft in 2007, Yahoo! in 2008, Google in 2009, Facebook in 2009, Paltalk in 2009, YouTube in 2010, AOL in 2011, Skype in 2011 and Apple in 2012. The speaker's notes in the briefing document reviewed by The Washington Post indicated that "98 percent of PRISM production is based on Yahoo, Google, and Microsoft". The slide presentation stated that much of the world's electronic communications pass through the U.S., because electronic communications data tend to follow the least expensive route rather than the most physically direct route, and the bulk of the world's internet infrastructure is based in the United States. The presentation noted that these facts provide United States intelligence analysts with opportunities for intercepting the communications of foreign targets as their electronic data pass into or through the United States. Snowden's subsequent disclosures included statements that government agencies such as the United Kingdom's GCHQ also undertook mass interception and tracking of internet and communications data – described by Germany as "nightmarish" if true – allegations that the NSA engaged in "dangerous" and "criminal" activity by "hacking" civilian infrastructure networks in other countries such as "universities, hospitals, and private businesses", and alleged that compliance offered only very limited restrictive effect on mass data collection practices (including of Americans) since restrictions "are policy-based, not technically based, and can change at any time", adding that "Additionally, audits are cursory, incomplete, and easily fooled by fake justifications", with numerous self-granted exceptions, and that NSA policies encourage staff to assume the benefit of the doubt in cases of uncertainty.

The slides Below are a number of slides released by Edward Snowden showing the operation and processes behind the PRISM program. The "FAA" referred to is Section 702 of the FISA Amendments Act ("FAA"), and not the widely known Federal Aviation Administration (FAA).

The French newspaper Le Monde disclosed new PRISM slides (see pages 4, 7 and 8) coming from the "PRISM/US-984XN Overview" presentation on October 21, 2013. The British newspaper The Guardian disclosed new PRISM slides (see pages 3 and 6) in November 2013 which on the one hand compares PRISM with the Upstream program, and on the other hand deals with collaboration between the NSA's Threat Operations Center and the FBI.

The program

… excerpt ends here. Continue reading the full article.

Illustrations

PRISM illustration
PRISM illustration
PRISM illustration
PRISM illustration
PRISM illustration

Worked examples

Example 1 — a first encounter with PRISM

Start with the simplest possible case. Write down what PRISM claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to PRISM before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about PRISM ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of PRISM

In research
PRISM appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses PRISM in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
PRISM is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2013 scandals, American secret government programs, Computer surveillance, so understanding it makes those chapters shorter.
In everyday life
Look for PRISM outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study PRISM in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what PRISM means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain PRISM out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PRISM in simple terms?

PRISM is a code name for a program under which the United States National Security Agency (NSA) collects internet communications from various U.S. internet companies. The program is also known by the SIGAD US-984XN.

Why does PRISM matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study PRISM?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on PRISM.

Tags

  • 2013 scandals
  • American secret government programs
  • Computer surveillance
  • Counterterrorism in the United States
  • Espionage
  • GCHQ operations
  • George W. Bush administration controversies
  • Human rights in the United States
  • Intelligence agency programmes revealed by Edward Snowden
  • Law enforcement in the United States
  • Mass surveillance
  • National Security Agency

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