computer science

NSA cryptography

NSA cryptography is a computer science 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 NSA cryptography rather than just read about it. In short: The vast majority of the National Security Agency's work on encryption is classified, but from time to time NSA participates in standards processes or otherwise publishes information about its cryptographic algorithms. The NSA has categorized encryption items into four product types, and algorithms into two suites.

Key takeaways

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

Reference excerpt

The vast majority of the National Security Agency's work on encryption is classified, but from time to time NSA participates in standards processes or otherwise publishes information about its cryptographic algorithms. The NSA has categorized encryption items into four product types, and algorithms into two suites. The following is a brief and incomplete summary of public knowledge about NSA algorithms and protocols.

Type 1 Product

A Type 1 Product refers to an NSA endorsed classified or controlled cryptographic item for classified or sensitive U.S. government information, including cryptographic equipment, assembly or component classified or certified by NSA for encrypting and decrypting classified and sensitive national security information when appropriately keyed.

Type 2 Product

A Type 2 Product refers to an NSA endorsed unclassified cryptographic equipment, assemblies or components for sensitive but unclassified U.S. government information.

Type 3 Product

Unclassified cryptographic equipment, assembly, or component used, when appropriately keyed, for encrypting or decrypting unclassified sensitive U.S. Government or commercial information, and to protect systems requiring protection mechanisms consistent with standard commercial practices. A Type 3 Algorithm refers to NIST endorsed algorithms, registered and FIPS published, for sensitive but unclassified U.S. government and commercial information.

Type 4 Product

A Type 4 Algorithm refers to algorithms that are registered by the NIST but are not FIPS published. Unevaluated commercial cryptographic equipment, assemblies, or components that are neither NSA nor NIST certified for any Government usage.

Algorithm Suites

Suite A

A set of NSA unpublished algorithms that is intended for highly sensitive communication and critical authentication systems.

Suite B

A set of NSA endorsed cryptographic algorithms for use as an interoperable cryptographic base for both unclassified information and most classified information. Suite B was announced on 16 February 2005, and phased out in 2016.

Commercial National Security Algorithm Suite

A set of cryptographic algorithms promulgated by the National Security Agency as a replacement for NSA Suite B Cryptography until post-quantum cryptography standards are promulgated.

Quantum resistant suite

In August 2015, NSA announced that it is planning to transition "in the not distant future" to a new cipher suite that is resistant to quantum attacks. "Unfortunately, the growth of elliptic curve use has bumped up against the fact of continued progress in the research on quantum computing, necessitating a re-evaluation of our cryptographic strategy." NSA advised: "For those partners and vendors that have not yet made the transition to Suite B algorithms, we recommend not making a significant expenditure to do so at this point but instead to prepare for the upcoming quantum resistant algorithm transition."

See also NSA encryption systems Speck and Simon, light-weight block ciphers, published by NSA in 2013

References

Worked examples

Example 1 — a first encounter with NSA cryptography

Start with the simplest possible case. Write down what NSA cryptography claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, 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 NSA cryptography 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 NSA cryptography 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 NSA cryptography

In research: NSA cryptography appears in computer science 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 NSA cryptography 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: NSA cryptography is common in secondary-school and first-year university syllabi. It links to neighbouring topics National Security Agency, National Security Agency cryptography, National Security Agency encryption devices, so understanding it makes those chapters shorter.
In everyday life: Look for NSA cryptography 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 NSA cryptography in 20 minutes

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

Frequently asked questions

What is NSA cryptography in simple terms?

Why does NSA cryptography matter?

Because it connects several computer science 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 NSA cryptography?

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 NSA cryptography.