computer science

SHA instruction set

SHA instruction set 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 SHA instruction set rather than just read about it. In short: A SHA instruction set is a set of extensions to the ARM, RISC-V and x86 instruction set architecture which support hardware acceleration of the Secure Hash Algorithm (SHA) family. ARM SHA-1 and SHA-256 instructions appeared as optional features (FEAT_SHA1 and FEAT_SHA256) in the Arm V8.0 architecture introduced in 2011.

Key takeaways

SHA instruction set 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 SHA instruction set to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of SHA instruction set from memory before moving on to harder problems.

Reference excerpt

A SHA instruction set is a set of extensions to the ARM, RISC-V and x86 instruction set architecture which support hardware acceleration of the Secure Hash Algorithm (SHA) family.

ARM SHA-1 and SHA-256 instructions appeared as optional features (FEAT_SHA1 and FEAT_SHA256) in the Arm V8.0 architecture introduced in 2011. The instructions are:

SHA-1: SHA1C, SHA1H, SHA1M, SHA1P, SHA1SU0, SHA1SU1 SHA-256: SHA256H, SHA256H2, SHA256SU0, SHA256SU1

SHA-512 and SHA-3 instructions appeared as optional features (FEAT_SHA512 and FEAT_SHA3) in the Arm V8.2 architecture. The instructions are:

SHA-512: SHA512H, SHA512H2, SHA512SU0, SHA512SU1 SHA-3: EOR3, RAX1, XAR, BCAX A scalable vector extension (SVE) version of the SHA-3 instructions appeared as an optional feature (FEAT_SVE_SHA3) in the Arm V9.0 architecture.

RISC-V SHA2 instructions are part of the Zknh extension part of the RISC-V Cryptography Extensions Volume I: Scalar & Entropy Source Instructions ratified in November 2021.

x86 architecture processors The original SSE-based extensions added four instructions supporting SHA-1 and three for SHA-256 and were specified in 2013 by Intel. Instructions for SHA-512 were introduced in Arrow Lake and Lunar Lake in 2024. .

SHA-1: SHA1RNDS4, SHA1NEXTE, SHA1MSG1, SHA1MSG2 SHA-256: SHA256RNDS2, SHA256MSG1, SHA256MSG2 The newer SHA-512 instruction set comprises AVX-based versions of the original SHA instruction set marked with a V prefix and these three new AVX-based instructions for SHA-512:

VSHA512RNDS2, VSHA512MSG1, VSHA512MSG2

AMD All recent AMD processors support the original SHA instruction set:

AMD Zen (2017) and later processors.

Intel The following Intel processors support the original SHA instruction set:

Intel Goldmont (2016) and later Atom microarchitecture processors. Intel Cannon Lake (2018/2019), Ice Lake (2019) and later processors for laptops ("mainstream mobile"). Intel Rocket Lake (2021) and later processors for desktop computers. The following Intel processors support the newer SHA-512 instruction set:

Intel Arrow Lake and Lunar Lake processors.

References

External links Chapter 8 of "Intel Architecture Instruction Set Extensions Programming Reference" (PDF). Archived from the original (PDF) on 2013-09-29.

Worked examples

Example 1 — a first encounter with SHA instruction set

Start with the simplest possible case. Write down what SHA instruction set 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 SHA instruction set 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 SHA instruction set 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 SHA instruction set

In research: SHA instruction set 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 SHA instruction set 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: SHA instruction set is common in secondary-school and first-year university syllabi. It links to neighbouring topics AMD, Hardware acceleration, Instruction set extensions, so understanding it makes those chapters shorter.
In everyday life: Look for SHA instruction set 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 SHA instruction set in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what SHA instruction set 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 SHA instruction set out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SHA instruction set in simple terms?

A SHA instruction set is a set of extensions to the ARM, RISC-V and x86 instruction set architecture which support hardware acceleration of the Secure Hash Algorithm (SHA) family. ARM SHA-1 and SHA-256 instructions appeared as optional features (FEAT_SHA1 and FEAT_SHA256) in the Arm V8.0 architectu…

Why does SHA instruction set 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 SHA instruction set?

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 SHA instruction set.