science

SEED

SEED 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 SEED rather than just read about it. In short: SEED is a block cipher developed by the Korea Information Security Agency (KISA). It is used broadly throughout South Korean industry, but seldom found elsewhere.

Key takeaways

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

Reference excerpt

SEED is a block cipher developed by the Korea Information Security Agency (KISA). It is used broadly throughout South Korean industry, but seldom found elsewhere. It gained popularity in Korea because 40-bit encryption was not considered strong enough, so the Korea Information Security Agency developed its own standard. However, this decision has historically limited the competition of web browsers in Korea, as no major SSL libraries or web browsers supported the SEED algorithm, requiring users to use an ActiveX control in Internet Explorer for secure web sites. On April 1, 2015 the Ministry of Science, ICT and Future Planning (MSIP) announced its plan to remove the ActiveX dependency from at least 90 percent of the country's top 100 websites by 2017. Instead, HTML5-based technologies will be employed as they operate on many platforms, including mobile devices. Starting with the private sector, the ministry plans to expand this further to ultimately remove this dependency from public websites as well.

Design SEED is a 16-round Feistel network with 128-bit blocks and a 128-bit key. It uses two 8 × 8 S-boxes which, like those of SAFER, are derived from discrete exponentiation (in this case, x247 and x251 – plus some "incompatible operations"). It also has some resemblance to MISTY1 in the recursiveness of its structure: the 128-bit full cipher is a Feistel network with an F-function operating on 64-bit halves, while the F-function itself is a Feistel network composed of a G-function operating on 32-bit halves. However the recursion does not extend further because the G-function is not a Feistel network. In the G-function, the 32-bit word is considered as four 8-bit bytes, each of which is passed through one or the other of the S-boxes, then combined in a moderately complex set of boolean functions such that each output bit depends on 3 of the 4 input bytes. SEED has a fairly complex key schedule, generating its thirty-two 32-bit subkeys through application of its G-function on a series of rotations of the raw key, combined with round constants derived (as in TEA) from the Golden ratio.

Use and adoption SEED has been adopted by several standard protocols: S/MIME (RFC 4010), TLS/SSL (RFC 4162), IPSec (RFC 4196), and ISO/IEC 18033-3:2010. NSS software security library in Mozilla's Gecko platform has implemented support for SEED, and Mozilla Firefox as of 3.5.4 supports SEED as a TLS cipher; however, Mozilla decided to drop the support of SEED by default in Firefox 27 and above because support for SEED has not had any practical positive effect in terms of helping South Korea migrate away from ActiveX-based e-commerce, and other browsers are not offering any SEED-based cipher suites. NSS still supports SEED-based cipher suites. The Linux kernel has supported SEED since 2007. Bloombase supports SEED in their full suite of data cryptography solutions.

References

External links SEED - KISA (Official Site, in Korean) SEED official specification document Archived 2013-04-30 at the Wayback Machine (English) RFC 4269: The SEED encryption algorithm (obsoletes RFC 4009) RFC 4010: Use of the SEED Encryption Algorithm in Cryptographic Message Syntax (CMS) RFC 4162: Addition of SEED Cipher Suites to Transport Layer Security (TLS) RFC 4196: The SEED Cipher Algorithm and Its Use with IPsec ISO/IEC 18033-3:2010

Worked examples

Example 1 — a first encounter with SEED

Start with the simplest possible case. Write down what SEED 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 SEED 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 SEED 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 SEED

In research: SEED 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 SEED 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: SEED is common in secondary-school and first-year university syllabi. It links to neighbouring topics Block ciphers, Feistel ciphers, Internet in South Korea, so understanding it makes those chapters shorter.
In everyday life: Look for SEED 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 SEED in 20 minutes

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

Frequently asked questions

What is SEED in simple terms?

SEED is a block cipher developed by the Korea Information Security Agency (KISA). It is used broadly throughout South Korean industry, but seldom found elsewhere.

Why does SEED 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 SEED?

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 SEED.