The "createToken" method returns an object of type TokenProviderResponse. Similar to the TokenProviderParameters object, this just holds a collection of objects that is parsed by the STS operation to construct a response to the client. The properties are:
Element token- The (DOM) token that was created by the TokenProvider.
String tokenId- The ID of the token
long lifetime- The lifetime of the token
byte entropy- Any entropy associated with the token
long keySize- The key size of a secret key associated with the token.
boolean computedKey- Whether a computed key algorithm was used in generating a secret key.
TokenReference attachedReference- An object which gives information how to refer to the token when it is "attached".
TokenReference unAttachedReference- An object which gives information how to refer to the token when it is "unattached".
Most of these properties are optional as far as the STS operation is concerned, apart from the token and token ID. The TokenReference object contains information about how to refer to the token (direct reference vs. Key Identifier, etc.), that is used by the STS to generate the appropriate reference to return to the client.