science

Red Pike (cipher)

Red Pike (cipher) is a 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 Red Pike (cipher) rather than just read about it. In short: Red Pike is a classified United Kingdom government encryption algorithm, proposed for use by the National Health Service by GCHQ, but designed for a "broad range of applications in the British government". Little is publicly known about Red Pike, except that it is a block cipher with a 64-bit block size and 64-bit key length.

Key takeaways

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

Reference excerpt

Red Pike is a classified United Kingdom government encryption algorithm, proposed for use by the National Health Service by GCHQ, but designed for a "broad range of applications in the British government". Little is publicly known about Red Pike, except that it is a block cipher with a 64-bit block size and 64-bit key length. According to the academic study of the cipher cited below and quoted in a paper by Ross Anderson and Markus Kuhn, it "uses the same basic operations as RC5" (add, XOR, and left shift) and "has no look-up tables, virtually no key schedule and requires only five lines of code"; "the influence of each key bit quickly cascades" and "each encryption involves of the order of 100 operations". 64 bits of key entropy are not considered secure anymore. Red Pike is available to approved British government contractors in software form, for use in confidential (not secret) government communication systems. GCHQ also designed the Rambutan cryptosystem for the same segment. Given that Red Pike is a British encryption algorithm, its name likely refers to a particular fell in the western English Lake District.

Supposed source code In February 2014, the supposed source code for Red Pike was posted as follows to the Cypherpunk mailing list.

Worked examples

Example 1 — a first encounter with Red Pike (cipher)

Start with the simplest possible case. Write down what Red Pike (cipher) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In 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 Red Pike (cipher) 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 Red Pike (cipher) 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 Red Pike (cipher)

In research: Red Pike (cipher) appears in 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 Red Pike (cipher) 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: Red Pike (cipher) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Block ciphers, GCHQ, so understanding it makes those chapters shorter.
In everyday life: Look for Red Pike (cipher) 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 Red Pike (cipher) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Red Pike (cipher) 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 Red Pike (cipher) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Red Pike (cipher) in simple terms?

Why does Red Pike (cipher) matter?

Because it connects several 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 Red Pike (cipher)?

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 Red Pike (cipher).