• Refactoring part of CASESession to be more fuzzable/testable by making it the structure more modular and closer to a data-in data-out design.

Changes in the PR

Sending Sigma1

1. All TLV encoding for Sigma1 has been encapsulated into the new EncodeSigma1() method; removing the bits from Networking and Messaging layers --> that way it could be tested without needing SessionManager and ExchangeContext.

HandleSigma1_and_SendSigma2

1. HandleSigma1_and_SendSigma2:

   • previously, this method was primarily a wrapper to HandleSigma1(); which in turn handled with all the validation and parsing of Sigma1 as well as the generation, and logic involved in sending Sigma2 or Sigma2Resume...in a very sequential manner.

   • Fix: This was changed to be more modular, by factoring out the Sending Sigma2 calls out of HandleSigma1(), and encapsulating it in a switch-case statement, and then breaking down Sigma2 Sending methods into two more methods: one for generating and preparing the Logic for the Sigma2, and one for Encoding it into TLV-format.

2. ParseSigma1(): made the output in the form of a struct, and decoupling it from exchange context, which was moved to HandleSigma1()

3. EncodeSigma2() and EncodeSigma2Resume(): created and refactored into them the TLV encoding for the final Sigma2/Sigma2Resume messages that will be sent.

4. PrepareSigma2() and PrepareSigma2Resume() : refactored into them all the steps that happen before Encoding the Sigma2/Sigma2Resume messages.

• Partially resolves: Use symbolic names for TLV tags in CASE #10091 and CASESession.cpp and PASESession.cpp should be using named tag #30476

Testing

• Added Unit Tests, CI Validation