U5.5 Implementing at the Transport layer

U5.5 Implementing at the Transport layer

1. Whereas the network level provided a stateless connection the transport layer delivers a reliable stream of bytes.

2. The transport layer also interfaces directly to the application

   • This interface between the two layers can be expanded to include security

3. 2 Advantages

   • traffic can be protected end-to-end making use of the reliable communication
   • The application has control over when the protection is used.
     • This means that the secure channel can cater for the requirements of the particular application giving its user some flexibility.
       • Example: if encryption is not supplied as part of the application, the secure channel can be used to provide confidentiality of data
     • A secure channel is often used to provide secure, single sign-on between client and server where the authentication services of encryption are used to strongly authenticate a client without necessarily involving the user

4. Disadvantages

   • for the application to have control over when a secure channel is invoked.
     • Applications must be modified or proxied to be able to invoke the secure channel
       • each application that needs to use a secure channel must either be modified to implement the secure channel or have a piece of proxy code purpose-built for it
   • The fact that implementing a secure channel at the transport level requires modification of applications or proxy code is a disadvantage
     • such code has to be developed on an application-by-application basis