Seed
The Korea Information Security Agency developed SEED to replace weak 40-bit encryption standards in South Korea. This decision emerged because 40-bit encryption was not considered strong enough for local needs. The agency created its own standard to ensure robust security within the country. Widespread adoption followed quickly throughout South Korean industry. However, this choice has historically limited competition among web browsers in Korea. No major SSL libraries or web browsers supported the SEED algorithm initially. Users had to rely on an ActiveX control in Internet Explorer for secure websites.
SEED is a 16-round Feistel network with 128-bit blocks and a 128-bit key. It uses two 8 × 8 S-boxes derived from discrete exponentiation. These S-boxes utilize x247 and x251 plus some incompatible operations. The structure resembles MISTY1 through its recursiveness. A 128-bit full cipher operates as a Feistel network with an F-function handling 64-bit halves. That F-function itself is a Feistel network composed of a G-function operating on 32-bit halves. The recursion stops there since the G-function is not a Feistel network. In the G-function, each 32-bit word splits into four 8-bit bytes passed through one of the S-boxes. Output bits depend on three of the four input bytes via complex boolean functions. The key schedule generates thirty-two 32-bit subkeys using rotations and round constants from the Golden ratio.
SEED has been adopted by several standard protocols including S/MIME (RFC 4010). It also appears in TLS/SSL under RFC 4162 and IPSec under RFC 4196. ISO/IEC 18033-3:2010 further formalized its use. NSS software security library in Mozilla's Gecko platform implemented support for SEED. Mozilla Firefox version 3.5.4 supported SEED as a TLS cipher. However, Mozilla decided to drop default support in Firefox 27 and above. This decision followed because SEED had no practical positive effect helping South Korea migrate away from ActiveX-based e-commerce. Other browsers were not offering any SEED-based cipher suites at that time. NSS still supports SEED-based cipher suites despite the default change. The Linux kernel has supported SEED since 2007. Bloombase includes SEED in their full suite of data cryptography solutions.
No major SSL libraries or web browsers supported the SEED algorithm initially. Users required an ActiveX control in Internet Explorer for secure websites. This requirement historically limited competition among web browsers in Korea. The reliance on ActiveX created barriers for other browser vendors entering the market. Most international users never encountered this specific constraint outside South Korea. The situation persisted until government intervention began shifting priorities toward broader compatibility. Browser developers faced pressure to either integrate SEED or lose access to Korean markets. The technical limitation became a significant hurdle for global standardization efforts.
On the 1st of April 2015 the Ministry of Science, ICT and Future Planning announced its plan to remove ActiveX dependency. The target was to eliminate this requirement from at least 90 percent of the country's top 100 websites by 2017. HTML5-based technologies would replace older methods as they operate on many platforms including mobile devices. Starting with the private sector, the ministry planned to expand further to public websites eventually. This initiative aimed to break the cycle of browser lock-in caused by legacy controls. Government agencies coordinated with industry leaders to implement new standards across digital infrastructure. The transition marked a deliberate shift away from proprietary dependencies toward open web technologies.
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Common questions
Who developed the SEED block cipher algorithm?
The Korea Information Security Agency developed the SEED block cipher to replace weak 40-bit encryption standards in South Korea. This agency created its own standard to ensure robust security within the country.
What are the technical specifications of the SEED block cipher?
SEED is a 16-round Feistel network with 128-bit blocks and a 128-bit key that uses two 8 × 8 S-boxes derived from discrete exponentiation. The structure resembles MISTY1 through its recursiveness and generates thirty-two 32-bit subkeys using rotations and round constants from the Golden ratio.
When did the Ministry of Science ICT and Future Planning announce plans to remove ActiveX dependency for SEED?
On the 1st of April 2015 the Ministry of Science, ICT and Future Planning announced its plan to remove ActiveX dependency. The target was to eliminate this requirement from at least 90 percent of the country's top 100 websites by 2017.
Why did Mozilla Firefox drop default support for the SEED algorithm?
Mozilla decided to drop default support in Firefox 27 and above because SEED had no practical positive effect helping South Korea migrate away from ActiveX-based e-commerce. Other browsers were not offering any SEED-based cipher suites at that time.
Which standard protocols adopted the SEED block cipher after its creation?
SEED has been adopted by several standard protocols including S/MIME under RFC 4010 and TLS/SSL under RFC 4162. ISO/IEC 18033-3:2010 further formalized its use while NSS software security library implemented support for SEED.