The document transmission phase

After a successful three-way-authentication requests and replies between the web client and server may be transmitted securely. The server offers its documents via the

secure offers page (cf. Figure ); on the client side the user selects a document and activates the corresponding CGI program upon confirmation. The call of the CGI program is not encrypted; however, the information regarding which document has been requested by the user must be encrypted at the client side.

In this phase only tokens of the type Cont are transmitted; the Plasma application is wired to call the filter function getDocument() for reverting the cryptographic operations on this token type. In this phase plaintext data are passed onto Plasma for cryptographic operations using the putDocument() API function.

The CGI program Cont.cgi gets called on the server side. It decrypts the information on the requested document and encrypts the document itself prior to transmission. The HTML pages sent in this phase represent the documents or offers of the server; the exact protocol is shown in Figure .

  

Figure: Interactions in the data transmission phase