Initiates asynchronous (DC) certificate generation.
Call this method to initiate an asynchronous certificate generation process. Pass the obtained async state to the DC server for signing. To finalize the generation, pass the async state received from the DC server to GenerateAsyncEnd.
AsyncState is a message of the distributed cryptography (DC) protocol. DC protocol is based on exchange of async states between a DC client (an application that wants to sign a PDF, XML, or Office document) and a DC server (an application that controls access to the private key). An async state can carry one or more signing requests, comprised of document hashes, or one or more signatures produced over those hashes.
In a typical scenario you get a client-side async state from the SignAsyncBegin method. This state contains document hashes to be signed on the DC server side. You then send the async state to the DC server (often represented by the DCAuth control), which processes it and produces a matching signatures state. The async state produced by the server is then passed to the SignAsyncEnd method.