Eku

EKU is an acronym that can refer to several different entities and concepts. The two most common uses are Eastern Kentucky University, a public university in Kentucky, and Extended Key Usage, a certificate extension in digital security. This article outlines these meanings briefly.

Eastern Kentucky University (EKU) is a public university located in Richmond, Kentucky. Founded in 1906 as the Kentucky State Normal School, it evolved into a comprehensive regional university with additional campuses in Manchester and Corbin. EKU offers a range of undergraduate and graduate programs through multiple colleges, serving a diverse student body and emphasizing education, business, science, and the humanities.

Extended Key Usage (EKU) is an X.509 certificate extension that specifies the intended purposes for which the certificate may be used. The extension contains a set of Object Identifiers (OIDs) that designate allowed uses, such as server authentication (1.3.6.1.5.5.7.3.1), client authentication (1.3.6.1.5.5.7.3.2), code signing (1.3.6.1.5.5.7.3.3), and email protection (1.3.6.1.5.5.7.3.4). The standard OID for the extension is 2.5.29.37. In practice, EKU can affect whether a certificate is accepted for a given operation; some certificates omit EKU or rely on policy to determine permitted uses.