(#174) Initial support to parametrize public-key and symmetric-key algorithms.

[gapisback]

This commit lays down the plumbing to parametrize the names of the public-key and symmetric-key algorithms that will be used by the simple_app. Currently, these are hard-coded to 'Enc_method_rsa_2048' and 'Enc_method_aes_256_cbc_hmac_sha256', respectively.

This commit now supports --public_key_alg and --symmetric_key_alg flags that can be supplied to the simple_app/example_app.exe program.

An initial list of char *Enc_public_key_algorithms[] and char *Enc_symmetric_key_algorithms[] has been created in src/certifier_algorithms.cc. The idea is that we can run test-executions choosing pairs of these algorithms to drive the simple_app.

High-level changes:

• Support --public_key_alg and --symmetric_key_alg flags which can be supplied [only] to the simple_app/example_app.exe program.

• An initial list of char Enc_public_key_algorithms[] and char Enc_symmetric_key_algorithms[] has been created in src/certifier_algorithms.cc

• run_example.sh:

  • Refactor methods implementing simple_app_python tests into their own functions as argument-parsing is different for C++ v/s Python apps. (New args added with this work are n/a for the Python simple_app.)

  • Add new test-method run_test-crypto_algorithms(), which will exercise the sub-steps needed to run simple_app with different pairs of crypto algorithms.

• CI/test.sh, build.yml: Add test-simple_app-with-crypto_algorithms, which will invoke said test case. This invokes run_test-crypto_algorithms() named earlier.

  • Pulled-out testing of simple_app_python with 'warm-restart' functionality into its own test-case invocation.
  • Adds test-simple_app_python-with-warm-restart().

• Cleaned-up some dependency of 'setup' step for simple_apps to reduce CI test run-times.

[gapisback]

Hi, @jlmucb - I did a minor rework of this change-set subsequent to our discussion this morning.

See the diffs applied in this commit.

There are still some things that do not work:

1. Using ecc-384 as a public-key algorithm name.
2. Using any one of these as an authenticated symmetric-key algorithm name: aes-128-cbc-hmac-sha256, or aes-256-cbc-hmac-sha384, aes-256-gcm. These run into limitations as documented in run_example.sh around L3214.

I'd like to get the bulk of the rest of this testing / refactoring machinery reviewed and merged.

Then, you / I can separately investigate why the choice of these diff crypto algorithms is not working.