The TScCertSubjectKeyIdExtension class defines a string that identifies a certificate's subject key identifier (SKI).
The SKI provides a unique identification for the subject of the certificate. The SKI is often used when working with XML digital signing.
The SKI extension identifies the public key certified by this certificate. This extension provides a way of distinguishing public keys if more than one is available for a given subject name.
This extension is specified in RFC 5280 section 188.8.131.52.