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.

A seed is an embryonic plant enclosed in a protective outer covering known as the seed coat.