Tutorial Using Keys
A key in the XML Security Library is a representation of the dsig:KeyInfo element and consists of several key data objects. The "value" key data usually contains a pointer to the actual key, while other key data objects may contain additional information about the key (e.g. X509 certificates). All key data objects within the same key are associated with that key.
The XML Security Library has several "invisible" key data classes. These classes never appear in a key's list of key data, but are used for processing dsig:KeyInfo (dsig:KeyName, enc:EncryptedKey, ...). As with transforms, an application can add custom key data objects or replace the default ones.