computer science

Simultaneous Authentication of Equals

Simultaneous Authentication of Equals 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 Simultaneous Authentication of Equals rather than just read about it. In short: In cryptography, Simultaneous Authentication of Equals (SAE) is a password-based authentication and password-authenticated key agreement method. Authentication SAE is a variant of the Dragonfly Key Exchange defined in RFC 7664, based on Diffie–Hellman key exchange using finite cyclic groups which can be a primary cyclic group or an elliptic curve.

Key takeaways

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

Reference excerpt

In cryptography, Simultaneous Authentication of Equals (SAE) is a password-based authentication and password-authenticated key agreement method.

Authentication SAE is a variant of the Dragonfly Key Exchange defined in RFC 7664, based on Diffie–Hellman key exchange using finite cyclic groups which can be a primary cyclic group or an elliptic curve. The problem of using Diffie–Hellman key exchange is that it does not have an authentication mechanism. So the resulting key is influenced by a pre-shared key and the MAC addresses of both peers to solve the authentication problem.

Use

IEEE 802.11s

SAE was originally implemented for use between peers in IEEE 802.11s. When peers discover each other (and security is enabled) they take part in an SAE exchange. If SAE completes successfully, each peer knows the other party possesses the mesh password and, as a by-product of the SAE exchange, the two peers establish a cryptographically strong key. This key is used with the "Authenticated Mesh Peering Exchange" (AMPE) to establish a secure peering and derive a session key to protect mesh traffic, including routing traffic.

WPA3

In January 2018, the Wi-Fi Alliance announced WPA3 as a replacement to WPA2. The new standard uses 128-bit encryption in WPA3-Personal mode (192-bit in WPA3-Enterprise) and forward secrecy. The WPA3 standard also replaces the pre-shared key (PSK) exchange with Simultaneous Authentication of Equals as defined in IEEE 802.11-2016 resulting in a more secure initial key exchange in personal mode. The Wi-Fi Alliance also claims that WPA3 will mitigate security issues posed by weak passwords and simplify the process of setting up devices with no display interface.

Security In 2019 Eyal Ronen and Mathy Vanhoef (co-author of the KRACK attack) released an analysis of WPA3's Dragonfly handshake and found that "an attacker within range of a victim can still recover the password" and the bugs found "allow an adversary to impersonate any user, and thereby access the Wi-Fi network, without knowing the user's password."

See also Extensible Authentication Protocol (EAP) Key-agreement protocol KRACK IEEE 802.1X

References

Further reading Harkins, Dan (Aug 20, 2008). "Simultaneous Authentication of Equals: A Secure, Password-Based Key Exchange for Mesh Networks". 2008 Second International Conference on Sensor Technologies and Applications (Sensorcomm 2008). pp. 839–844. doi:10.1109/SENSORCOMM.2008.131. ISBN 978-0-7695-3330-8. S2CID 18401678 – via IEEE Xplore. Vanhoef, Mathy; Ronen, Eyal (2019-04-10). "Dragonblood: Analyzing the Dragonfly Handshake of WPA3 and EAP-pwd". IEEE Symposium on Security & Privacy. IEEE.

Worked examples

Example 1 — a first encounter with Simultaneous Authentication of Equals

Start with the simplest possible case. Write down what Simultaneous Authentication of Equals 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 Simultaneous Authentication of Equals 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 Simultaneous Authentication of Equals 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 Simultaneous Authentication of Equals

In research: Simultaneous Authentication of Equals 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 Simultaneous Authentication of Equals 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: Simultaneous Authentication of Equals is common in secondary-school and first-year university syllabi. It links to neighbouring topics Authentication protocols, Computer network security, Cryptographic protocols, so understanding it makes those chapters shorter.
In everyday life: Look for Simultaneous Authentication of Equals 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 Simultaneous Authentication of Equals in 20 minutes

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

Frequently asked questions

What is Simultaneous Authentication of Equals in simple terms?

In cryptography, Simultaneous Authentication of Equals (SAE) is a password-based authentication and password-authenticated key agreement method. Authentication SAE is a variant of the Dragonfly Key Exchange defined in RFC 7664, based on Diffie–Hellman key exchange using finite cyclic groups which c…

Why does Simultaneous Authentication of Equals 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 Simultaneous Authentication of Equals?

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 Simultaneous Authentication of Equals.